Mandibular gland secretions of meliponine worker bees: further evidence for their role in interspecific and intraspecific defence and aggression and against their role in food source signalling

Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location. We studied Trigona spinipes and Scaptotrigona aff. depilis (`postica`), two sympatric species to which this hypothesis was applied. Using extracts of carefully dissected glands instead of crude cephalic extracts we analysed the substances contained in the mandibular glands of worker bees. Major components of the extracts were 2-heptanol (both species), nonanal (T. spinipes), benzaldehyde and 2-tridecanone (S. aff. depilis). The effect of mandibular gland extracts and of individual components thereof on the behaviour of worker bees near their nest and at highly profitable food sources was consistent. Independent of the amount of mandibular gland extract applied, the bees overwhelmingly reacted with defensive behaviour and were never attracted to feeders scented with mandibular gland extract or any of the synthetic chemicals tested. Both bee species are capable of using mandibular gland secretions for intra-and interspecific communication of defence and aggression and share 2-heptanol as a major pheromone compound. While confirming the role of the mandibular glands in nest defence, our experiments provide strong evidence against their role in food source signalling.

Social separation and diazepam withdrawal increase anxiety in the elevated plus-maze and serotonin turnover in the median raphe and hippocampus

The present work aimed to evaluate the effects of social separation for 14 days (chronic stress) and of withdrawal from a 14-day treatment with diazepam (acute stress) on the exploratory behaviour of male rats in the elevated plus-maze and on serotonin (5-hydroxytryptamine) turnover in different brain structures. Social separation had an anxiogenic effect, evidenced by fewer entries into, and less time spent on the open arms of the elevated plus-maze. Separation also selectively increased 5-hydroxytryptamine turnover in the hippocampus and median raphe nucleus. Diazepam withdrawal had a similar anxiogenic effect in grouped animals and increased 5-hydroxytryptamine turnover in the same brain structures. Chronic treatment with imipramine during the 14 days of separation prevented the behavioural and neurochemical changes caused by social separation. It is suggested that the increase in anxiety determined by both acute and chronic stress is mediated by the activation of the median raphe nucleus-hippocampal 5-hydroxytryptamine pathway.

Separation and hedging results with state-contingent production

A state-contingent model of production under uncertainty is developed and compared with more traditional models of production under uncertainty. Producer behaviour with both production and price risk, in the presence and in the absence of futures and forward markets, is analysed in this state-contingent framework. Conditions for the optimal hedge to be positive or negative are derived. We also show that, under plausible conditions, a risk-averse producer facing price uncertainty and the ability to hedge price risk will never willingly adopt a nonstochastic technology. New separation results, which hold in the presence of both price and production risk, are then developed. These separation results generalize Townsend's spanning results by reducing the number of necessary forward markets by one.

Candida colonisation as a source for candidaemia

Candida spp. are important healthcare-associated pathogens. Identifying the source of infection is important for prevention and control strategies. The objective of this study was to evaluate candida colonisation sites as potential sources for candidaemia. Sixty-three consecutive patients with a positive blood culture for candida were included. Surveillance cultures were collected from urine, rectum, oropharynx, skin, intravascular catheter tip and skin around catheter. Molecular typing was performed when the same species of candida was isolated from blood and surveillance sites of a patient. C. albicans was associated with 42% of candidaemias, C. parapsilosis 33%, C. tropicalis 16% and C. guilliermondii, C. krusei, C. glabrata, C. holmii and C. metapsilosis were all 2% each. Six of 10 C. parapsilosis catheter tip isolates were indistinguishable from corresponding blood isolates (all in neonates). C. albicans isolates from blood were indistinguishable from corresponding gastrointestinal, tract isolates in 13 of 26 patients and from catheter tip isolates in two patients. In conclusion, the results suggest that gastrointestinal colonisation is the probable source of C. albicans candidaemia and C. parapsilosis is exogenous. (C) 2009 The Hospital, Infection Society. Published by Elsevier Ltd. All rights reserved.

Effects of semen storage and separation techniques on sperm DNA fragmentation

Objective: To determine the effect of semen storage and separation techniques on sperm DNA fragmentation. Design: Controlled clinical study. Setting: An assisted reproductive technology laboratory. Patient(s): Thirty normoozospermic semen samples obtained from patients undergoing infertility evaluation. Intervention(s): One aliquot from each sample was immediately prepared (control) for the sperm chromatin dispersion assay (SCD). Aliquots used to assess storage techniques were treated in the following ways: snap frozen by liquid nitrogen immersion, slow frozen with Tris-yolk buffer and glycerol, kept on ice for 24 hours or maintained at room temperature for 4 and 24 hours. Aliquots used to assess separation techniques were processed by the following methods: washed and centrifuged in media, swim-up from washed sperm pellet, density gradient separation, density gradient followed by swim-up. DNA integrity was then measured by SCD. Main Outcome Measure(s): DNA fragmentation as measured by SCD. Result(s): There was no significant difference in fragmentation among the snap frozen, slow frozen, and wet-ice groups. Compared to other storage methods short-term storage at room temperature did not impact DNA fragmentation yet 24 hours storage significantly increased fragmentation. Swim-up, density gradient and density gradient/swim-up had significantly reduced DNA fragmentation levels compared with washed semen. Postincubation, density gradient/swim-up showed the lowest fragmentation levels. Conclusion(s): The effect of sperm processing methods on DNA fragmentation should be considered when selecting storage or separation techniques for clinical use. (Fertil Steril (R) 2010;94:2626-30. (C) 2010 by American Society for Reproductive Medicine.)

Isolation of transcripts overexpressed in the human pathogen Trichophyton rubrum grown in lipid as carbon source

Trichophyton rubrum is the most common etiological agent of human dermatophytosis. Despite the incidence and medical importance of this dermatophyte, little is known about the mechanisms of host invasion and pathogenicity. Host invasion depends on the adaptive cellular responses of the pathogen that allow it to penetrate the skin layers, which are mainly composed of proteins and lipids. In this study, we used suppression subtractive hybridization to identify transcripts over-expressed in T rubrum cultured in lipid as carbon source. Among the subtractive cDNA clones isolated, 85 clones were positively screened by cDNA array dot blotting and were sequenced. The putative proteins encoded by the isolated transcripts showed similarities to fungal proteins involved in metabolism, signaling, defense, and virulence, such as the MDR/ABC transporter, glucan 1,3-beta-glucosidase, chitin synthase B, copper-sulfate-regulated protein, and serine/threonine phosphatase (calcineurin A). These results provide the first molecular insight into the genes differentially expressed during the adaptation of T. rubrum to a lipidic carbon source.

OCT findings in macular hole formation in eyes with complete vitreofoveal separation

The current study describes the morphologic macular features in two eyes that developed full-thickness macular holes in the setting of documented vitreofoveal separation. Using third-generation optical coherence tomography, complete vitreofoveal separation associated with the disruption of the inner foveal retina was documented in both cases. Five months after presentation, decreased vision and epiretinal membrane formation associated with development of a full-thickness macular hole were observed in the first patient. In the second patient, a full-thickness macular hole was demonstrated by optical coherence tomography 6 weeks after presentation. These findings suggest that full-thickness macular holes may develop in eyes with vitreofoveal separation. Evidence of the disturbance of the inner foveal architecture on optical coherence tomography indicates the potential role of factors other than anteroposterior or oblique vitreoretinal tractional forces in the genesis of some full-thickness macular holes.

Long-Term Maternal Separation Differentially Alters Serum Corticosterone Levels and Blood Neutrophil Activity in A/J and C57BL/6 Mouse Offspring

Objectives: In this work, we searched for maternal separation effects on serum corticosterone levels and blood neutrophil activity in adult male A/J and C57BL/6 mouse offspring. Methods: 40 male A/J mice and 40 male C57BL/6 mice were divided within each strain into two groups. Mice in the maternal separation group were separated from their mothers (1 h/day) on postnatal days 0-13. Mice in the control group were left undisturbed. On postnatal day 45, blood was drawn from all mice and used to assess neutrophil activity by flow cytometry and serum corticosterone levels by radioimmunoassay. Results: The results showed that each mouse strain responded differently to maternal separation, but in both cases, serum corticosterone levels were affected. In both strains, adult mice that experienced maternal separation showed lower serum corticosterone levels than control mice. In relation to control mice kept together with their mothers, the levels of serum corticosterone were 72.7 and 36.36% lower in A/J and C57BL/6 mice submitted to maternal separation, respectively. The current findings showed that maternal separation increased neutrophil activity in mice after reaching adulthood. The observed effects, although in the same direction, differed between A/J and C57BL/6 mice. Maternal separation increased both the percentage and intensity of phagocytosis in C57BL/6 mice, but had no effects on A/J mice. Furthermore, maternal separation increased basal and propidium iodide-labeled Staphylococcus aureus-induced oxidative burst in A/J mice but did not affect oxidative burst in C57BL/6 mice. Finally, phorbol myristate acetate-induced oxidative burst increased in both strains. Conclusion: These results indicate that early maternal separation increases innate immunity, most likely by modifying hypothalamus-pituitary-adrenal axis activity. This suggests that maternal separation is a good model for stress which produces long-term neuroimmune changes whatever the animal species and strain used. Copyright (C) 2011 S. Karger AG, Basel

Ecological distribution of mosquito larvae of the Anopheles punctulatus group on Niolam (Lihir) Island, Papua New Guinea

We surveyed the larval habitats of member,, of the Anopheles punctulatus group of mosquitoes on Niolam (Lihir) Island. Papua New Guinea. Identification of this group was undertaken by polymerase chain reaction-restriction fragment length polymorphism analysis of the amplified internal transcribed spacer unit 2 of rDNA. because morphologic separation of member species is unreliable. The most widespread malaria vector species and their most common larval habitats identified to aid source-reduction programs for malaria control. The most ubiquitous species was An. punctulatus, followed by An. farauti no. 2. then An. farauti s.s. Anopheles punctulatus has increased relative to An.farauti s.l. since the start of development projects on Lihir Island. The most common larval habitats were shallow temporary pools with clay substrate and with plants or floatage. These habitats. mostly encountered alongside poorly drained roads, may be increased by development projects.