Cytotoxicity of Piper aduncum (Piperaceae) essential oil in brown stink bug Euschistus heros (Heteroptera: Pentatomidae).

Euschistus heros (F.) (Hemiptera: Pentatomidae) is a soybean pest in Brazil, controlled with synthetic chemical insecticides, which may be harmful to the environment and humans, as well as to select pest resistant strains. The research for new pest control strategies such as the use of plant essential oils has been increased due to the selectivity and biodegradation of these molecules. The objective was to evaluate the cytological changes in the salivary glands, fat body and midgut of E. heros exposed to different concentrations of essential oil of Piper aduncum L. (Piperales: Piperaceae), which the main compounds were identified as myristicin 30.03%, aromadendrene 9.20%, dillapiole 8.43%, α-serinene 7.31%, tridecane 6.26%, γ-elemene 4.58% and o-cymene 4.20%. The essential oil of P. aduncum was toxic for E. heros with LD50 = 36.23 mg per insect and LD90 = 50.42 mg per insect. Cytological changes such as tissue disruption, increase in mitochondria population, and glycogen and lipid depletion occur in the fat body cells, whereas salivary glands and midgut are not affected by this essential oil. Results suggest that P. aduncum essential oil causes fat body cellular stress, which may compromise some physiological processes for the insect survival.

Ultrastructural analysis of salivary glands in a phytophagous stink bug revealed the presence of unexpected muscles.

The exceptional abilities of stink bugs (Hemiptera: Pentatomidae) to colonize a diverse group of plants have been attributed to the feeding behaviors and the functions of the salivary complex of these insects. Here, we describe the ultrastructure of the salivary glands of the Neotropical brown stink bug, Euschistus heros, which is a major component of the pentatomid pest complex on soybeans, Glycine max, in the neotropics. Our results revealed a salivary gland complex consisting of two lobes (i.e., anterior and posterior), with a constriction between them (i.e., the hilum), in which the salivary and accessory gland ducts are inserted. The principal gland epithelium has a single layer of cells lining an enlarged lumen filled with saliva, and these cells are cuboidal, rich in rough endoplasmic reticulum and secretory vesicles, with well-developed nuclei, all of which are typical features of protein-secreting cells. We report, for the first time in insects, the presence of a layer of muscle cells surrounding the columnar hilum epithelium. The accessory salivary gland cells are cuboidal with nuclei containing condensed chromatin and cytoplasm rich in vacuoles and rough endoplasmic reticulum, indicating the potential involvement of these glands in water transport/secretion. The lumen content of each lobe of the principal gland suggests that the lobes produce different compounds. Thus, our results suggest that the E. heros salivary complex might have unconventional mechanisms to mix/release saliva, which might help explain the polyphagous abilities of these insects.

Bioactivity of six plant extracts on adults of Demotispa neivai (Coleoptera: Chrysomelidae).

Demotispa neivai Bondar (Coleoptera: Chrysomelidae) damage oil palm fruits, which makes it necessary to develop products to control this insect. The mortality, repellency, and antifeeding effects on adults of D. neivai of six plant extracts of Azadirachta indica A. Juss. (Sapindales: Meliaceae), Ricinus communis (L.) (Malpighiaes: Euphorbiaceae), Citrus sinensis Oesbek (Sapindales: Rutaceae), Nicotiana tabacum (L.) (Slanales: Solanaceae), Capsicum annuum (L.) (Solanales: Solanaceae), and Artemisia absinthium (L.) (Asterales: Asteraceae) were determined: 1) the lethal concentration LC50-90, lethal time of D. neivai was evaluated after spraying the fruits of oil palm; 2) repellent effects of each ingredient were evaluated by calculating the index of repellency; 3) antifeeding effects with the rate of inhibition calculated between doses of 20 and 24 g/liter. The mortality of D. neivai was higher with the extracts Ci. sinensis, R. communis, N. tabacum, and Ca. annuum. The mortality of D. neivai increased in the first 72 hr in all treatments. The extracts of N. tabacum, Ca. annuum, and A. indica were more repellent to D. neivai that those of Ci. sinensis, Ar. Absinthium, and R. communis. Antifeeding effect was higher with Ci. sinensis and R. communis. The increased mortality of D. neivai by Ci. sinensis can be explained by the effect of this compound on the respiratory system of insects. Extracts of Ci. sinensis, R. communis, N. tabacum, and Ca. annuum repelled and caused mortality of D. neivai and, thus, can be used in integrate pest management programs of this pest in oil palm plantations.

Staff doses in interventional radiology: a national survey.

PURPOSE: To present the results of occupational radiation doses investigated through a national survey promoted by the National Society of Interventional Radiology in Spain. MATERIALS AND METHODS: The monthly dosimetric records of 28 interventional radiologists from 10 hospitals were analyzed and filtered to remove inconsistent dosimeter readings. The evaluation of the results includes different workloads as well as different radiation protection habits. RESULTS: Poor use of personal dosimetry by some interventional radiologists was brought to light. Most professionals do not use an over-apron dosimeter as recommended by the International Commission on Radiological Protection. Ceiling-suspended protective screens are used irregularly in many cases. All interventionalists perform digital subtraction angiographic imaging from a control room in more than 80% of procedures. The maximum monthly doses recorded were 3.8 mSv under the apron, 20.2 mSv over the apron, and 63.1 mSv to the hands. CONCLUSIONS: For under-apron and hand readings, extrapolated median values were below 30% of annual dose limits, but in the case of over-apron readings, the extrapolated median dose was higher than the newly recommended limit for the eye lens of 20 mSv per year. This study mainly highlights the need to use radiation protection tools and personal dosimeters to protect staff and monitor eye lens doses.

A parametrization of the CT number of a substance and its use for stoichiometric calibration.

A method to carry out stoichiometric calibrations of CT scanners employed in radiotherapy treatment planning is proposed. The method is based on a simple parametrization of the CT number of a substance, which involves only two variables to describe the substance (electron density and one effective atomic number) and one parameter to describe the beam. The method was tested experimentally on a group of beams. A set of no tissue-like substances of known densities and elemental compositions were employed as calibrators. CT number-to-density curves (RED curves) were calculated with the proposed parametrization and compared to those measured with a commercial density phantom. Differences between the electron densities assigned by the calculated RED curves and the measured ones were in the range 0.009-0.019 (RMS). The proposed method may be employed to carry out accurate stoichiometric calibrations by using only one suitable substance as calibrator, not necessarily tissue-like.