Potential interspecific competition and host specificity: hispine beetles on Heliconia

Abstract. 1. Adults of rolled-leaf hispine beetles (Chrysomelidae, Coleoptera) spend their lives in the scrolls formed by immature leaves of Heliconia (Heli-coniaceae, Monocotyledonae) in Tropical America. As many as eight hispine species can intermingle in the host scrolls at a single site. Scrolls of single host species are invariably occupied by adults of more than one hispine species, and as many as five species can simultaneously occupy one scroll.
2. I made virgin scrolls, which had never contained any insects, by growing leaves under the cover of plastic bags.
3. Thirty-seven combinations of single hispine and Heliconia species were experimentally created in the virgin scrolls, at two sites and in two seasons, in Costa Rica. Combinations included all abundant host species at the sites.
4. All beetles left all leaves of the twenty-eight unnatural beetle—host combinations, within 24 h. On the other hand, none of the nine natural combinations was completely abandoned within the experimental period.
5. Thus, host specificity is not broader in the absence of similar hispine species that might be competitors, and interspecies competition does not affect this obvious aspect of resource utilization for these phytophagous insects.     

Oviposition choice and larval survival of Dasineura marginemtorquens (Diptera: Cecidomyiidae) on resistant and susceptible Salix viminalis

Abstract.

• 1 Substantial intraspecific variation exists in Salix viminalis resistance to the gall midge Dasineura marginemtorquens. Earlier work has found this variation to have a large genetic component. Willow clones are stable in their resistances between midge generations and different nutrient levels in both field and laboratory culture.
• 2 This study reports the results of laboratory experiments on female oviposition choice and larval survival on potted plants from clones that are very different in resistance as determined in field studies.
• 3 In choice experiments using pairs of plants, the average female midge did not prefer susceptible willow clones over resistant ones for oviposition. In about one third of the replicates, midges actually laid more eggs on the resistant clone. Further work is necessary to examine the nature of variation among midges in discrimination of these plant types.
• 4 Resistance is manifested as great differences in larval survival. Six days after oviposition survival was 92% on susceptible plants but only 6% on resistant ones. Galls developed on all of the susceptible plants, while in 73% of the resistant plants galls were not even initiated.
• 5 The plant traits causing resistance are enigmatic. Larval behaviour suggests that resistant plants interfere with feeding behaviour. On resistant plants, most larvae wander for more than 24 h without initiating any galls before dying. On susceptible plants many first instar larvae begin feeding and initiate galls within this period.

     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Aspects of the Water Relations of Ileostylus micranthus (Hook. f.) Tieghem, a New Zealand Mistletoe

Leaf water potentials in the mistletoe, Ileostylus micranthusgrowing outdoors decreased rapidly during the early part ofthe day but remained relatively steady in the early afternoondespite increases in atmospheric vapour pressure deficit (vpd).Minimum water potentials of the mistletoe were relatively constant.They were held at values lower than those of hosts when thelatter maintained high water potentials but approached or evenexceeded those of hosts when they developed low water potentials.In contrast, cut shoots of Ileostylus usually maintained higherwater contents and leaf water potentials than those of its hostswhen both were desiccated separately in the laboratory. Pressure-volumeanalyses indicated that Ileostylus had lower water potentialat full turgor, a lower water potential but higher relativewater content at turgor loss, and a higher bulk modulus of elasticitythan the following four hosts: the native Kunzea ericoides andCoprosmapropinqua, and the introduced Ribes sanguineum and Teline monspessulana.Water potential at turgor loss (_tlp) was strongly correlatedwith the minimum field water potential of both mistletoes andhosts. When _tlpof mistletoe and host is similar (as on Kunzeaand Ribes) field water potentials are also similar, but when_tlpis lower in the mistletoe (as on Coprosma and Teline), thefield water potential of the mistletoe is lower than that ofits host. Consequently, I. micranthus is likely to be more frequenton hosts that maintain high field water potentials than on hoststhat develop low water potentials. Copyright 1999 Annals ofBotany Company Water relations, water potential, osmotic potential, pressure-volume, Ileostylus micranthus , mistletoe, New Zealand.     

Ultrasound imaging in an experimental model of fatty liver disease and cirrhosis in rats

Background

Atypical scrapie was first identified in Norwegian sheep in 1998 and has subsequently been identified in many countries. Retrospective studies have identified cases predating the initial identification of this form of scrapie, and epidemiological studies have indicated that it does not conform to the behaviour of an infectious disease, giving rise to the hypothesis that it represents spontaneous disease. However, atypical scrapie isolates have been shown to be infectious experimentally, through intracerebral inoculation in transgenic mice and sheep. The first successful challenge of a sheep with 'field' atypical scrapie from an homologous donor sheep was reported in 2007.

Results

This study demonstrates that atypical scrapie has distinct clinical, pathological and biochemical characteristics which are maintained on transmission and sub-passage, and which are distinct from other strains of transmissible spongiform encephalopathies in the same host genotype.

Conclusions

Atypical scrapie is consistently transmissible within AHQ homozygous sheep, and the disease phenotype is preserved on sub-passage.     

Fracture prevention in COPD patients; a clinical 5-step approach

Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV₁ < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture.     

Evidence for cadherin-11 cleavage in the synovium and partial characterization of its mechanism

IntroductionEngagement of the homotypic cell-to-cell adhesion molecule cadherin-11 on rheumatoid arthritis (RA) synovial fibroblasts with a chimeric molecule containing the cadherin-11 extracellular binding domain stimulated cytokine, chemokine, and matrix metalloproteinases (MMP) release, implicating cadherin-11 signaling in RA pathogenesis. The objective of this study was to determine if cadherin-11 extracellular domain fragments are found inside the joint and if a physiologic synovial fibroblast cleavage pathway releases those fragments.MethodsCadherin-11 cleavage fragments were detected by western blot in cell media or lysates. Cleavage was interrupted using chemical inhibitors or short-interfering RNA (siRNA) gene silencing. The amount of cadherin-11 fragments in synovial fluid was measured by western blot and ELISA.ResultsSoluble cadherin-11 extracellular fragments were detected in human synovial fluid at significantly higher levels in RA samples compared to osteoarthritis (OA) samples. A cadherin-11 N-terminal extracellular binding domain fragment was shed from synovial fibroblasts after ionomycin stimulation, followed by presenilin 1 (PSN1)-dependent regulated intramembrane proteolysis of the retained membrane-bound C-terminal fragments. In addition to ionomycin-induced calcium flux, tumor necrosis factor (TNF)-α also stimulated cleavage in both two- and three-dimensional fibroblast cultures. Although cadherin-11 extracellular domains were shed by a disintegrin and metalloproteinase (ADAM) 10 in several cell types, a novel ADAM- and metalloproteinase-independent activity mediated shedding in primary human fibroblasts.ConclusionsCadherin-11 undergoes ectodomain shedding followed by regulated intramembrane proteolysis in synovial fibroblasts, triggered by a novel sheddase that generates extracelluar cadherin-11 fragments. Cadherin-11 fragments were enriched in RA synovial fluid, suggesting they may be a marker of synovial burden and may function to modify cadherin-11 interactions between synovial fibroblasts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0647-9) contains supplementary material, which is available to authorized users.