Termite soldiers contribute to social immunity by synthesizing potent oral secretions.

The importance of soldiers to termite society defence has long been recognized, but the contribution of soldiers to other societal functions, such as colony immunity, is less well understood. We explore this issue by examining the role of soldiers in protecting nestmates against pathogen infection. Even though they are unable to engage in grooming behaviour, we find that the presence of soldiers of the Darwin termite, Mastotermes darwiniensis, significantly improves the survival of nestmates following entomopathogenic infection. We also show that the copious exocrine oral secretions produced by Darwin termite soldiers contain a high concentration of proteins involved in digestion, chemical biosynthesis, and immunity. The oral secretions produced by soldiers are sufficient to protect nestmates against infection, and they have potent inhibitory activity against a broad spectrum of microbes. Our findings support the view that soldiers may play an important role in colony immunity, and broaden our understanding of the possible function of soldiers during the origin of soldier-first societies.

Nosema ceranae alters a highly conserved hormonal stress pathway in honeybees.

Nosema ceranae, an emerging pathogen of the western honeybee (Apis mellifera), is implicated in recent pollinator losses and causes severe energetic stress. However, whether precocious foraging and accelerated behavioural maturation in infected bees are caused by the infection itself or via indirect energetic stress remains unknown. Using a combination of nutritional and infection treatments, we investigated how starvation and infection alters the regulation of adipokinetic hormone (AKH) and octopamine, two highly conserved physiological pathways that respond to energetic stress by mobilizing fat stores and increasing search activity for food. Although there was no response from AKH when bees were experimentally infected with N. ceranae or starved, supporting the notion that honeybees have lost this pathway, there were significant regulatory changes in the octopamine pathway. Significantly, we found no evidence of acute energetic stress being the only cause of symptoms associated with N. ceranae infection. Therefore, the parasite itself appears to alter regulatory components along a highly conserved physiological pathway in an infection-specific manner. This indicates that pathogen-induced behavioural alteration of chronically infected bees should not just be viewed as a coincidental short-term by-product of pathogenesis (acute energetic stress) and may be a result of a generalist manipulation strategy to obtain energy for reproduction.

Disease associations between honeybees and bumblebees as a threat to wild pollinators.

Emerging infectious diseases (EIDs) pose a risk to human welfare, both directly and indirectly, by affecting managed livestock and wildlife that provide valuable resources and ecosystem services, such as the pollination of crops. Honeybees (Apis mellifera), the prevailing managed insect crop pollinator, suffer from a range of emerging and exotic high-impact pathogens, and population maintenance requires active management by beekeepers to control them. Wild pollinators such as bumblebees (Bombus spp.) are in global decline, one cause of which may be pathogen spillover from managed pollinators like honeybees or commercial colonies of bumblebees. Here we use a combination of infection experiments and landscape-scale field data to show that honeybee EIDs are indeed widespread infectious agents within the pollinator assemblage. The prevalence of deformed wing virus (DWV) and the exotic parasite Nosema ceranae in honeybees and bumblebees is linked; as honeybees have higher DWV prevalence, and sympatric bumblebees and honeybees are infected by the same DWV strains, Apis is the likely source of at least one major EID in wild pollinators. Lessons learned from vertebrates highlight the need for increased pathogen control in managed bee species to maintain wild pollinators, as declines in native pollinators may be caused by interspecies pathogen transmission originating from managed pollinators.

A realistic description of the charge carrier wave function in microcrystalline polymer semiconductors.

The electronic structure of the charge carrier in one of the most commonly used semiconducting polymers (poly(3-hexylthiophene (P3HT)) is described using a combination of classical and quantum chemical methods. It is shown that the carriers are localized in correspondence with long-lived traps which are present also in the crystalline phase of the polymer. The existence of activated transport for very ordered polymer phases (regardless of the strength of the polaron formation energy) is explained, and the trapped states, postulated by many phenomenological models, are described for the first time with chemical detail. It is shown that computational chemistry methods can be used to fill the gap between phenomenological descriptions of charge transport in polymers and microscopic descriptions of the individual quantum dynamic processes.

Squamous cell carcinoma of the tongue occurring as a subsequent malignancy in a 12-year-old acute leukemia survivor.

Squamous cell carcinoma of the tongue is rare in children and previously unreported as a second malignancy after survival of acute leukemia. Usual etiologic associations such as smoking and alcohol use are not commonly seen in this population, and exposure to immunosuppressive and antineoplastic agents including radiation therapy may contribute to the occurrence of these tumors. A review of the literature reveals only 21 previously reported cases of squamous cell carcinoma of the tongue in children less than 15 years old, and in only two cases was it a second malignancy; none were in leukemia survivors. Small numbers prevent accurate conclusions with regard to tumor behavior, but prognosis appears to be poor with aggressive invasion and early metastasis common. Follow-up of survivors of leukemia and its therapy with immunosuppressive and cytotoxic drugs and radiation should include regular careful head and neck examinations.

Melphalan-induced toxicity in nude mice following pretreatment with buthionine sulfoximine.

Melphalan-induced toxicity in nude mice following pretreatment with a regimen of L-buthionine sulfoximine (BSO), previously shown to enhance the activity of this alkylating agent against rhabdomyosarcoma and glioma xenografts, was examined. Mice were pretreated with i.p. BSO (2.5 mmol/kg x 7 doses at 12-h intervals plus concomitant availability of a 20-mM solution in the drinking water) or vehicle prior to a single i.p. injection of melphalan (35.65 mg/m2). As compared with control animals who received no BSO pretreatment, mice pretreated with BSO lost weight prior to therapy with melphalan (6.9% weight loss vs 0.3% weight gain; P less than 0.005) and showed a greater mean nadir weight loss after melphalan (3.8% vs. 2.1%; P = 0.049). Treatment with melphalan was associated with histologic evidence of reversible gastrointestinal toxicity, reversible myelosuppression, and histologic evidence of acute renal tubular necrosis, with no differences being observed between mice that had been pretreated with BSO and those that had been pretreated with vehicle. No evidence of cardiac, hepatic, or skeletal muscle toxicity was found in melphalan-treated animals. These results suggest that treatment of nude mice with melphalan following BSO-mediated depletion of glutathione does not result in enhanced organ toxicity despite an increase in the antineoplastic activity of this alkylating agent.

Chest wall mesenchymoma (hamartoma) in infancy. CT and MR findings.

A case of a chest wall mesenchymoma in a five month old infant is presented, and the role of CT and MR are emphasized. There have been no prior reports of the CT or MR findings in this entity.