Expression and hormonal control of a new larval cuticular multigene family at the onset of metamorphosis of the tobacco hornworm

The pattern of cuticular protein synthesis by the epidermis of the tobacco hornworm larva changes during the final day of feeding, leading to an alteration in cuticular structure and a stiffening of the cuticle. We have isolated a small multigene family which codes for at least three of the new cuticular proteins made at this time. The five genes which were isolated from this family map to two different genomic regions. Sequencing shows that one of the genes is 1.9 kb and consists of three exons coding for a 12.2-kDa acidic (pI = 5.26) protein that is predominantly hydrophilic. The deduced amino acid sequence shows regions of similarity to proteins from flexible lepidopteran cuticles and from Drosophila larval and pupal cuticles, but not to proteins found in highly sclerotized cuticles. This gene family is first expressed late on the penultimate day (Day 2) of feeding in the final larval instar and ceases expression 2 days later when metamorphosis begins. In situ hybridization shows that this gene family is expressed in all the epidermal cells of Day 3 larvae except the bristle cells and those at the muscle attachment site. Expression can be induced in Day 1 epidermis by exposure to 50 ng/ml 20-hydroxyecdysone in vitro, but only if juvenile hormone is absent. Its developmental expression, tissue specificity, and hormonal regulation strongly suggest that this multigene family is involved in the structural changes that occur in the larval cuticle just prior to the onset of metamorphosis.     

Viruses isolated from cells persistently infected with vesicular stomatitis virus show altered interactions with defective interfering particles.

Virus mutants isolated from persistent infections of vesicular stomatitis virus in BHK-21 cells were much less susceptible to interference mediated by the defective interfering particle used to establish the persistent infection. This mutational change occurred as early as 34 days in the persistent infection and continued for over 5 years. The earliest variants showed no oligonucleotide map changes and no difference in the temperature-sensitive phenotype from the original virus, but the later variants exhibited extensive map changes. These results suggest a possible role for defective interfering particles in the selection of the mutants.     

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.     

Biological activity of Manduca sexta allatotropin-like peptides,predicted products of tissue-specific and developmentally regulated alternatively spliced mRNAs

The insect neuropeptide, allatotropin (Manse-AT), exerts multiple functions including the stimulation of juvenile hormone (JH) biosynthesis in adults and the inhibition of active ion transport across the midgut epithelium of feeding larvae. The Manse-AT gene is expressed in multiple regions of the nervous system as three mRNAs that differ by alternative splicing. The specific mRNA isoform present differs in a tissue- and developmental-specific manner thus providing a mechanism for the regulated production of peptides specific to each isoform. These peptides are predicted to include three allatotropin-like (Manse-ATL) peptides that exhibit limited structural identity to Manse-AT and overlapping biological activities.     

Insect allatotropins belong to a family of structurally-related myoactive peptides present in several invertebrate phyla

Originally named for its ability to stimulate juvenile hormone production by lepidopteran corpora allata, allatotropin has emerged as a neuropeptide with multiple neural, endocrine and myoactive roles. This paper describes the experimental evidence for allatotropin action, its localization in several species of insects, and its multiple effects on a variety of different tissues that lead to increased hemolymph circulation and gut motility. The overall physiological effects may also include species-specific effects such as the regulation of nutrient absorption, modulation of the circadian cycle and migratory preparedness. In addition, we present evidence suggesting that allatotropins are members of a family of myoactive peptides found in several invertebrate phyla. Finally, we speculate that the myoactive properties of allatotropins are basal and it is likely that the stimulatory action of allatotropins on juvenile hormone synthesis evolved secondarily.     

Alternative splicing of transcripts expressed by the Manduca sexta allatotropin (Mas-AT) gene is regulated in a tissue-specific manner

The Manduca allatotropin (Mas-AT) gene is expressed as at least three mRNA isoforms that differ from each other by alternative splicing. The location at which the alternative exons are included in the mature mRNAs occur within the open reading frame, so that three different propeptides are predicted as translation products. In the pharate adult insect, the major mRNA isoform expressed in the brain and frontal ganglion differs from that expressed in the nerve cord. Examination of the deduced translations of the alternative exons reveals the presence of three additional Mas-AT-like sequences that are flanked by basic amino acid residues. Therefore, the Mas-AT-like sequences present within the gene may be derived from a duplication of an ancestral Mas-AT-like sequence followed by divergence.     

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.