Compounds released by disturbed adults of the haematophagous bug Triatoma infestans (Hemiptera: Reduviidae): behavioural effects of single compounds and binary mixtures

Adults of the Chagas disease vector Triatoma infestans Klug (Hemiptera: Reduviidae: Triatominae), possess paired exocrine glands: the metasternal and Brindley's glands. Both glands are discharged by disturbed adults, releasing an alarm pheromone that elicits an escape response of larvae. The present study analyzes the individual (or combined) effects of some of the volatiles of the whole pheromone blend released under disturbance, searching for active compounds and for possible interactions (e.g. synergism, additive effects) between them. Using an experimental arena, different doses of components emitted by disturbed adults are tested against larvae. Larvae show escape responses to some of the acids, as well as to one alcohol, but no response to ketones. This is observed with certain doses of compounds from Brindley's glands (isobutyric, butyric and acetic acid; 2‐methyl‐1‐butanol), although the compounds tested in the present study that are produced by metasternal glands are shown to evoke random responses, suggesting that mainly Brindley's glands are involved in the alarm context. Two combinations of two individually repellent compounds (2‐methyl‐1‐butanol with acetic or isobutyric acid) evoke escape responses, although other combinations make the individual effect disappear. A different mixture of two individually repellent compounds (butyric and isobutyric acid) evokes attraction, although these are also host odours. The potential use of the active compounds released by disturbed adults to monitor triatomine populations is discussed.     

Male specific natural products in the bug, Leptoglossus phyllopus: Chemistry and possible function

In the Coreoidea and some allied groups, male adults possess an abdominal gland opening through a midventral ostiole in the 7–8th abdominal intersegmental membrane. Using a GC-MS system, the following aromatic volatiles were identified in the abdominal gland secretion from males of the leaf footed bug, Leptoglossus phyllopus: guaiacol, benzyl alcohol, syringaldehyde, methyl p-hydroxybenzoate, acetosyringone, and vanillin. Males from which the glands were removed still mated and were competitive with control males for a limited number of females. The ventral abdominal gland secretion may act as a long-range attractant of females. The possibility that attraction of females by males in Heteroptera is an adaptation facilitating colonization of successional habitats is discussed.     

Volatile compounds emitted by Triatoma dimidiata,a vector of Chagas disease: chemical analysis and behavioural evaluation

In this study, we evaluated the responses of Triatoma dimidiata Latreille (Hemiptera: Reduviidae) to volatiles emitted by conspecific females, males, mating pairs and metasternal gland (MG) extracts with a Y‐tube olfactometer. The volatile compounds released by mating pairs and MGs of T. dimidiata were identified using solid‐phase microextraction and coupled gas chromatography‐mass spectrometry (GC‐MS). Females were not attracted to volatiles emitted by males or MG extracts; however, they preferred clean air to their own volatiles or those from mating pairs. Males were attracted to volatiles emitted by males, females, mating pairs, pairs in which the male had the MG orifices occluded or MG extracts of both sexes. However, males were not attracted to volatiles emitted by pairs in which the female had the MG orifices occluded. The chemical analyses showed that 14 and 15 compounds were detected in the headspace of mating pairs and MG, respectively. Most of the compounds identified from MG except for isobutyric acid were also detected in the headspace of mating pairs. Both females and males were attracted to octanal and 6‐methyl‐5‐hepten‐2‐one, and males were attracted to 3,5‐dimethyl‐2‐hexanol. Males but not females were attracted to a seven‐compound blend, formulated from compounds identified in attractive MG extracts.     

Chemical ecology of triatomine bugs: vectors of Chagas disease

Knowledge of chemical ecology of haematophagous triatomine bugs (Hemiptera: Heteroptera: Reduviidae) could be of practical value because this polyphyletic subfamily includes species of medical importance, such as vectors of Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae), the aetiological agent of Chagas disease. For particular species of Dipetalogaster, Panstrongylus, Rhodnius and Triatoma, therefore, we review information on exocrine glands and products, interpreting their apparent roles as semiochemicals in the aggregation, alarm, defence, host-finding and sexual behaviour of these Triatominae.     

Spectral analysis of Delayed Luminescence from human skin as a possible non-invasive diagnostic tool

In vivo measurements of Delayed Luminescence (DL), the low-level photo-induced emission which lasts for a longer time after switching off the excitation light, have been performed on human skin, with the aim to develop a technique for optical biopsy. Preliminary tests have been performed on healthy volunteers, measuring the time decays of the spectral components (λ_emiss = 400–800 nm) starting 10 μs after switching off the excitation (λ_exc = 337 nm). Significant differences in the decay trends of DL from different subjects were revealed and quite a good reproducibility for the same subject was observed. The modeling of experimental data has been examined in detail in order to get parameters, characterizing the theoretical fit, whose changes may be correlated with age differences and seasonal variations. Proceedings of the XVIII Congress of the Italian Society of Pure and Applied Biophysics (SIBPA), Palermo, Sicily, September 2006.     

Rainbow bee-eaters (Merops ornatus) as a monitoring tool for honeybees (Apis mellifera L.; Hymenoptera: Apidae)

Abstract Regurgitated pellets were collected from underneath roosts of rainbow bee-eaters in suburban Darwin, Australia, and examined for the presence of wings of honeybees. The proportion of pellets containing wings was compared prior to and after placement or removal of honeybee hives in the vicinity of four roosts. On each occasion, the addition or removal of hives was reflected in proportions of pellets containing wings. The results suggest that examination of pellets beneath bee-eater roosts would be a useful technique for monitoring the occurrence of feral honeybees. Potential uses for this technique in eradication of unwanted bees are discussed.     

T-cell responses to multiple antigens presented by RNA-transfected APCs: a possible immunomonitoring tool

The increasingly deeper understanding of how the immune system recognizes and destroys tumors promises to enable the development of new approaches for gene therapy and immunotherapy. However, a treatment that induces safe and potentially beneficial antitumor responses is expected to require stepwise refinements. As part of this challenge, assays are needed to measure specific antitumor immune responses in patients. This becomes problematic because most tumors express unknown tumor antigens and it is often difficult to obtain sufficient amounts of viable tumor material for in vitro assays. Recently it was demonstrated that RNA derived from tumor cells stimulated T cells in an antigen-specific manner. These studies have formed the basis for the development of dendritic cell vaccines that express tumor antigens following translation of tumor RNA. Therefore, it occurred to us that antigen-presenting cells transfected with total tumor RNA might also be valuable in monitoring the antitumor responses induced in patients who participate in clinical trials. To test this hypothesis, we developed a model in which Epstein-Barr virus (EBV)–transformed lymphoblastoid cell lines were used as a source of RNA. Since this RNA encodes for known EBV antigens, it was possible to determine whether the expected responses were observed. Our results show for the first time that T cells primed to APC transfected with RNA isolated from EBV-infected lymphocytes exhibited a fine specificity that enabled them to recognize individual EBV antigens.This work was supported by a Developmental Research Grant from the Derald H. Ruttenberg Cancer Center, Mount Sinai School of Medicine.     

The effect of moving air on detection of a 60-Hz electric field

Two potential mechanisms in detection of a 60-Hz electric field by albino rats were examined: field-induced movement of the vibrissae and field-induced vibration of the skin. Specifically, the experiment tested field detection in a moving stream of air designed to mask field-induced movement of the skin, fur, and vibrissae. Rats were trained to detect electric fields and were then tested at field intensities from 0–25 kV/m rms. As previously reported, rats demonstrate unmistakable behavioral evidence of field detection at all intensities above 7.5 kV/m. After establishing detection in still air, field detection was re-examined in moving air (average air velocity approximately 2.8–6.8 m/s). The primary result is that the wind produced no change in detection at field intensities above threshold (> 7.5 kV/m). Indeed, at these intensities detection was virtually identical in still and moving air. A secondary finding is that moving air produced statistically significant (P < .05) but apparently contradictory effects on detection when the field intensity was below threshold. On no-field trials the wind lowered scores (i.e., fewer presses on the field-off lever); however, on subthreshold field trials, the wind actually increased detection scores (i.e., more presses on the field-on lever). While this no-field and subthreshold field result is interesting and deserves further study, we place primary emphasis on the finding that, if the field was detectable in still air, it was also detectable in moving air. This result leads us to believe that movement of the vibrissae, fur, or skin is not likely to be the main mechanism of electric-field detection in our subjects. © 1993 Wiley-Liss. Inc.     

Anti-bromodeoxyuridine monoclonal antibody: an alternative tool for the identification of replicated DNA at the electron microscope level

A new method for identifying the replicated DNA at the electron microscope level is described. Cells were first exposed in vitro to 5-bromodeoxyuridine (BUdR) in conjunction with 5-fluorodeoxyuridine (FUdR) and BUdR incorporated into DNA was then detected on Lowicryl-embedded sections by immunogold technique using a monoclonal anti-BUdR antibody. After using this method, chromatin and chromosomes are strongly labelled.     

Ants as mealybug detectors: a novel tool for monitoring Planococcus ficus infestation based on ant behaviour

1. Vineyards are economically valuable agroecosystems that have spread to all continents. As such, sustainable management of their pests is an important goal. Mealybugs are serious pests of vines with Planococcus ficus (VMB) being the most problematic worldwide. Mealybugs are attended by different ant species, whose trophobiotic relationship is often considered damaging since some ant species may offer effective protection from natural enemies in exchange for honeydew.
2. We tested whether this trophobiosis can be used as a VMB monitoring tool, developing a protocol to evaluate infestation on the plants based on ant behaviour (Ant method). We compared this new protocol with the conventional one, consisting in visual counting of VMBs on infested leaves (Leaf method).
3. Our results demonstrated that the Ant method yielded significant advantages over the Leaf method by: (i) allowing to detect VMB infestation on individual plants much earlier; and (ii) allowing to keep track of VMB presence after pest treatments.
4. The Ant method is proposed as a valid complementary tool for integrated pest management in vineyards and its successful achievement encourage searching for further agricultural contexts in which ants may be revaluated as a monitoring tool.

     

The valve movement response of mussels: a tool in biological monitoring

Biological sensors are becoming more important to monitor the quality of the aquatic environment. In this paper the valve movement response of freshwater (Dreissena polymorpha) and marine (Mytilus edulis) mussels is presented as a tool in monitoring studies. Examples of various methods for data storage and data treatment are presented, elucidating easier operation and lower detection limits. Several applications are mentioned, including an early warning system based on this valve movement response of mussels.     

Stone handling by Japanese macaques (Macaca fuscata): Implications for tool use of stone

Stone-play, a newly innovated cultural behavior, has been observed among the free-ranging Arashiyama B troop Japanese macaques near Kyoto, Japan since 1979. Conditions in which the non-purposeful handling of stones might possibly give rise to tool behavior are discussed. The progression of this behavior is traced through three phases: transmission, tradition, and transformation. During the first two phases, through social learning, the behavior was established within the group as a regular item of their behavioral repertoire and was most frequently observed after eating provisioned grain. In the third phase, observations suggest a “faddish” shift in the practice of certain behavioral sub-types between 1984 and 1985. During this period young individuals increasingly began to carry stones away from the feeding station, mixing stone manipulation with forage-feeding activities in the forest. Observations suggest under such conditions, stone handling is likely to lead to the occasional use of stone as a tool. This conclusion probably can be applied to species other thanMacaca fuscata. Consideration of the eco-setting and social learning correlates of stone handling suggests how the instrumental use of stone might emerge from a tradition of non-instrumental manipulation.     

Quenching of DNA-ethidium fluorescence by amsacrine and other antitumor agents: a possible electron-transfer effect

The antitumor agent amsacrine, 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA), when bound to double-stranded DNA, particularly poly(deoxyadenylicthymidylic acid), reduced the fluorescence of bound ethidium without physically displacing it from DNA. Fluorescence lifetime measurements showed that the reduction of fluorescence was not due to reduction of the lifetime of the excited state of ethidium. Rather, a proportion of the DNA-bound ethidium changed to a state where the fluorescence was highly quenched. Several other 9-anilinoacridine derivatives, and also 9-hydroxyellipticine, caused quenching of ethidium-DNA fluorescence, whereas 9-aminoacridine, proflavin, and ellipticine had no effect. Resonance energy transfer (F?rster transfer) is not responsible for the effect since there is no spectral overlap between the absorption spectrum of any of the agents and the fluorescence emission spectrum of ethidium. It is suggested that quenching may occur as a result of reversible formation of electron-transfer complexes between the intercalating drug and the excited state of ethidium.     

Testosterone, endurance, and Darwinian fitness: natural and sexual selection on the physiological bases of alternative male behaviors in side-blotched lizards

The mechanistic bases of natural and sexual selection on physiological and behavioral traits were examined in male morphs of three colors of the side-blotched lizard, Uta stansburiana. Orange-throated males are aggressive and defend large territories with many females. Blue-throated males defend smaller territories with fewer females; however, blue-throated males assiduously mate guard females on their territory. Yellow-throated males do not defend a territory, but patrol a large home range. They obtain secretive copulations from females on the territories of dominant males. Males with bright orange throats had higher levels of plasma testosterone (T), endurance, activity, and home range size and concomitantly gained greater control over female home ranges than blue- or yellow-throated males. Experimentally elevating plasma T in yellow- and blue-throated males increased their endurance, activity, home range size, and control over female territories to levels that were seen in unmanipulated orange-throated males that had naturally high plasma T. However, the enhanced performance of orange-throated males is not without costs. Orange-throated males had low survival compared to the other morphs. Finally, some yellow-throated males transformed to a partial blue morphology late in the season and the endurance of these transforming yellow-throated males increased from early to late in the season. In addition, yellow-throated males that transformed to blue also had significantly higher plasma T late in the season compared to the plasma T earlier in the season. T appears to play an important role in the physiological changes that all three color morphs undergo during the process of maturation. In some yellow males, T plays an additional role in plastic changes in behavior and physiology late in the reproductive season. We discuss natural and sexual selection on physiological and behavioral traits that leads to the evolution of steroid regulation in the context of alternative male strategies.     

Quantitative genetics of natural variation of behavior in Drosophila melanogaster: the possible role of the social environment on creating persistent patterns of group activity

Using a set of nine effectively isogenic lines collected from nature in 1998, we observed unperturbed behaviors of mixed-sex groups of Drosophila melanogaster. We repeatedly scanned replicated groups of genetically identical individuals, five females and five males, and recorded the behavior of each individual (i.e., walking, feeding, grooming, flying, courting, mating, fighting, or resting). From these behaviors, we made a composite variable of activity for our quantitative genetic analysis. Genotypes differed in activity, explaining 14.41% of the variation in activity; 8.60% of the variation was explained by a significant genotype x sex interaction, which signifies genetic variation for sexual dimorphism in behavior. Phenotypic plasticity explained 11.13% of the variation in activity. Different genotypes and sexes within genotypes had different rank orders of the component behaviors that contribute to activity. We found no effect of common rearing environment. Instead, differences between replicate groups within genotype accounted for 19.47% variation in activity, and activity was significantly repeatable across scans. This emergent group behavior is likely caused by differences between groups of interacting individuals, even though individuals were genetically identical across groups. Thus, emergent group behavior explained almost as much variation in activity as the combined sources of genetic variation (23.01%), and this is an additional level on which selection could operate: individuals and groups. We discuss how differences among groups could change patterns of additive genetic variation available for evolution. Furthermore, because the behavior of an individual is influenced by conspecifics, genotype interactions between individuals could contribute to indirect selection. Finally, if we consider activity as a syndrome governing all component behaviors with strong genetic correlations among behaviors within an individual, then these component behaviors cannot evolve independently. These results suggest that reductionist approaches of molecular behavior genetics may be incomplete and/or misleading when considering similar phenotypes at the population level or when trying to understand how behaviors evolve.     

LC-NMR: a new tool to expedite the dereplication and identification of natural products

The rapid identification of known or undesirable compounds from natural products extracts — “dereplication” — is an important step in an efficiently run natural products discovery program. Dereplication strategies use analytical techniques and database searching to determine the identity of an active compound at the earliest possible stage in the discovery process. In the past few years, advances in technology have allowed the development of tandem analytical techniques such as liquid chromatography mass spectrometry (LC-MS), LC-MS-MS, liquid chromatography nuclear magnetic resonance (LC-NMR), and LC-NMR-MS. LC-NMR, despite its lower sensitivity as compared to LC-MS, provides a powerful tool for rapid identification of known compounds and identification of structure classes of novel compounds. LC-NMR is especially useful in instances where the data from LC-MS are incomplete or do not allow confident identification of the active component of a sample. LC-NMR has been used to identify the marine alkaloid aaptamine as the active component in an extract of the sponge Aaptos sp. This extract had been identified as an enzyme inhibitor by a high throughput screening (HTS) effort. Isolated aaptamine exhibited an IC₅₀=120 μM against this enzyme. Strategies for the identification of aaptamine and for the use of LC-NMR in a natural products HTS program are discussed. Journal of Industrial Microbiology & Biotechnology (2000) 25, 342–345. Received 30 March 2000/ Accepted in revised form 03 July 2000     

Fractal analysis of plant spatial patterns: a monitoring tool for vegetation transition shifts

Spatial heterogeneity, like species diversity, is an important ecosystem property. We examine the effects of land use on the diversity and spatial distribution of plants in five semi-arid communities of eastern Spain using non-linear methods to assess the spatialtemporal dynamics of plant populations. Specifically, we are interested in detecting long-term structural changes or drift in an ecosystem before it is too late to prevent irreversible degradation. Fractal analysis is used to characterize the complexity of plant spatial patterns and Information Theory indices are used to measure change in information flow with land use changes and soil substrate. We found that grazing favored diversity and heterogeneity of species distribution on the impoverished gypsum and saline substrate community, as opposed to the detrimental effect of grazing in the Alpha steppe community. Indeed, old-field succession after 30 years of abandonment showed a recovery of species diversity but not the spatial structure of the vegetation. Further, Information Fractal Dimension, representing the unpredictability of plant spatial patterns in the landscape, increased as we moved from a highly diverse to a less diverse community, revealing the change to a more scattered and homogeneous spatial plant distribution. The Information Fractal Dimension is a good estimator of ecosystem disturbance, independent of scale, and thus can be used to monitor ecosystem dynamics.     

农作物虫害的机器检测与监测技术研究进展

在早期发现并准确定位害虫, 对其未来的发展趋势作出评价, 可提高施药处方决策和综合防治的针对性和准确性。在作物虫害信息的获取中, 传统的检测和监测方法不但耗时、费力, 而且导致的预报滞后会进一步增加损失程度, 很难较好地满足现代农业的精准生产要求。本文介绍了国内外学者在田间作物上开展害虫及其危害状况的机器检测和监测技术研究取得的进展, 包括声特征检测法、雷达观测法、图像识别法以及光谱监测法等, 讨论了现有技术的局限性, 指出了未来作物虫害机器检测和监测技术的可能发展方向是采用多种技术相结合的组合式检测和监测方法, 从多个角度获取特定虫害的相关信息, 相互进行实证检验, 以提高作物虫害机器检测和监测的精度及效率。