IL-17F deficiency inhibits small intestinal tumorigenesis in Apc mice

IL-17 plays an important role in gut homeostasis. However, the role of IL-17F in intestinal tumorigenesis has not been addressed. Here we demonstrate that ablation of IL-17F significantly inhibits spontaneous intestinal tumorigenesis in the small intestine of Apc^Min/+ mice. IL-17F ablation decreased IL-1β and Cox-2 expression as well as IL-17 receptor C (IL-17RC) expression, which were increased in tumors from Apc^Min/+ mice. Lack of IL-17F did not reverse the splenomegaly but partially restored thymic atrophy, suggesting a local effect of IL-17F in the intestine. IL-17F deficient Apc^Min/+ mice showed a significant decrease in immune cell infiltration in the lamina propria. Interestingly, the expression of IL-17A from CD4 T cells in the lamina propria remains unchanged in the absence of IL-17F. Collectively, our results suggest the proinflammatory and essential role of IL-17F to develop spontaneous intestinal tumorigenesis in Apc^Min/+ mice in the presence of IL-17A.     

A Trifluoromethyl Analog of Verbenachalcone Promotes Neurite Outgrowth and Cell Proliferation of NeuroScreen-1 Cells

Past research has shown that natural products of plant and marine origins and their congeners enhance the actions of neuritogenic factors of the central nervous system (CNS) such as nerve growth factor (NGF). However, the role of fluorine substitutions in their structure–activity relationship (SAR) has not been explored. We have synthesized a trifluoromethyl analog of verbenachalcone (VC), a pharmacologically active natural compound previously shown to potentiate NGF activity. This analog, designated C278, enhances neurite outgrowth and proliferation of NeuroScreen-1™ (NS-1) cells, a subclone of PC12 pheochromocytoma cells. C278 increases the percentage of neurite bearing cells in the presence of suboptimal doses of NGF in comparison with controls treated with NGF alone. In addition, C278 stimulates cell growth in reduced serum and serum-free cell culture conditions based on our observation of increases in cell number and metabolic assessment with MTT reduction and resazurin assays. The addition of C278 partially restored inhibition of NGF-induced neurite outgrowth by the mitogen-activated protein kinase kinase (MEK) inhibitors PD98059 and U0126. Short-term sequential exposure of cells to U0126, C278, and NGF enhanced phosphorylation of extracellular signal-regulated kinase (ERK) in comparison with cells treated with only the MEK inhibitor and NGF. C278 also attenuated cell growth arrest caused by exposure to PD98059, U0126 and the phosphatidylinositol-3 kinase (PI3K) inhibitor, LY294002 but did not alter phosphorylation of Akt, a classic downstream target of PI3K during cell survival. These data suggest that C278 promotes NGF-dependent neurite outgrowth in NS-1 cells through a MEK signaling pathway by a mechanism that alters short-term activation of ERK. In contrast, C278 promotes PI3K-mediated survival independently of Akt phosphorylation.     

Quality control in homograft valve processing: when to screen for microbiological contamination?

Human donor heart valves remain essential for many reconstructive heart procedures. Heart valve donations are a scarce resource which must be used efficiently and safely. Infection transmission remains a potential risk with homograft valve use. Early experience with homograft valves identified high rates of microbial contamination at collection and initiated the practise of immersion in an antibiotic cocktail. Many centres rely on the microbiology screening after exposure to the antibiotic cocktail. We in our centre accept or reject valves on the basis of the microbiology screening at the time of collection prior to immersion in antibiotic solution. We wanted to compare our rate of valve discard and the rate of microbial contamination at implant with other centres. Valves are collected for the Irish Heart Valve Tissue Bank through partnership between the National Centre for Cardiothoracic Surgery and the Irish Blood Transfusion Service. Valves are collected in a surgical theatre setting and processed in dedicated section of the Irish Blood Transfusion Board. Tissues are screening for microbiology at collection and also at implantation. A total of 564 human heart valves and valve conduits were processed through the service during the study period. 167 (29.6%) were discarded during the processing and storage stages. The major reason for this in 117 cases was unsatisfactory microbiology on initial tissue screening. Repeat screening of accepted valves at the time of implantation identified positive cultures in only 0.9%. Optimal use of these limited resources is clearly important. However recipient safety remains paramount. One-fifth of collected valves are discarded at the processing stage due to positive microbiology screening. This is a higher rate of discard then other centres which reject 5.6–10% due to positive microbiology. However our rate of contamination at time of implant is lower then the 3% rate reported elsewhere. We are satisfied that our current discard rate, although significant, reflects rigorous quality control and the optimal balance between valve availability and patient safety.     

Biological interactions among extant and fossil clonal organisms

Biological interactions among clonal marine organisms are an important aspect of their behavior and are important in the construction of biological reefs. The interactions addressed here are among crustose and erect coralline algae, sponges, corals, and bryozoans, and may involve clones of the same species (conspecific), or different species (heterospecific). Conspecific interactions may be either between modules or clones that are produced asexually from one propagule, genetically identical, or between clones that are sexually produced from two or more propagules that may or may not be genetically identical. Juxtaposed genetically identical clones generally fuse whereas non-identical clones may or may not fuse, depending on their relatedness and histocompatibility. Most heterospecific clonal interactions are spatially competitive and result in overgrowths or stand-offs. Clone fission/fragmentation may occur as a result of biotic or abiotic processes that initially degrade but may eventually restore or even enhance ability to gain space and/or nutrients. Self-overgrowths also occur, usually over dead, diseased, or senescent parts of the same clone.     

Roles of clone–clone interactions in building reef frameworks: principles and examples

In living and fossil reefs, rapid upward clone growth provides positive topographic relief; the skeletal framework provides rigidity. Clonal organisms have been the chief frame-builders during most of the Phanerozoic; large clone size, growth habit, growth form, and arrangement of these clones in the framework result from rapid growth rates. Dense skeletal packing enhances rigidity and results in live–live interactions between juxtaposed clones. These interactions are both heterospecific and conspecific; the former mostly involve spatial competition whereas the latter involve clone fusion, self-overgrowth, and fission. We describe three types of fusion: (a) inter-clone fusion of two or more clones, each from a separate propagule; (b) intra-clone fusion of parts of the same clone having its origin from a single propagule; it includes recovery from partial clone degradation and self-overgrowth; (c) quasi-fusion between a live bud/polyp/zooid and a dead part (stem; branch) of the same or a different clone, i.e., a live-dead association.     

Trophic level and basal resource use of soil animals are hardly affected by local plant associations in abandoned arable land

Plants provide resources and shape the habitat of soil organisms thereby affecting the composition and functioning of soil communities. Effects of plants on soil communities are largely taxon‐dependent, but how different functional groups of herbaceous plants affect trophic niches of individual animal species in soil needs further investigation. Here, we studied the use of basal resources and trophic levels of dominating soil meso‐ and macrofauna using stable isotope ratios of carbon and nitrogen in arable fallow systems 3 and 14–16 years after abandonment. Animals were sampled from the rhizosphere of three plant species of different functional groups: a legume (Medicaco sativa), a nonlegume herb (Taraxacum officinale), and a grass (Bromus sterilis). We found virtually no consistent effects of plant identity on stable isotope composition of soil animals and on thirteen isotopic metrics that reflect general food‐web structure. However, in old fallows, the carbon isotope composition of some predatory macrofauna taxa had shifted closer to that of co‐occurring plants, which was particularly evident for Lasius, an aphid‐associated ant genus. Trophic levels and trophic‐chain lengths in food webs were similar across plant species and fallow ages. Overall, the results suggest that variations in local plant diversity of grassland communities may little affect the basal resources and the trophic level of prey consumed by individual species of meso‐ and macrofauna belowground. By contrast, successional changes in grassland communities are associated with shifts in the trophic niches of certain species, reflecting establishment of trophic interactions with time, which shapes the functioning and stability of soil food webs.     

On the PsbS-induced quenching in the plant major light-harvesting complex LHCII studied in proteoliposomes

Photosynthesis Research - Non-photochemical quenching (NPQ) in photosynthetic organisms provides the necessary photoprotection that allows them to cope with largely and quickly varying light...     

Development of transgenic strains for the biological control of the Mexican fruit fly, Anastrepha ludens

The Mexican fruit fly, Anastrepha ludens, is a highly significant agricultural pest species that has been genetically transformed with a piggyBac-based transposon vector system using independent vector and transposase helper plasmids. Minimum estimated germ-line transformation frequencies were approximately 13–21% per fertile G₀ individual, similar to previously reported frequencies using single vector-helper plasmids. Two vector constructs were tested with potential importance to transgenic strain development for mexfly biological control. The first allows post-integration stabilization of a transposon-vector by deletion of a terminal sequence necessary for mobilization. The complete pB[L1-EGFP-L2-DsRed-R1] vector was integrated into the Chiapas wild type strain with subsequent deletion of the L2-DsRed-R1 sub-vector carrying the piggyBac 3′ terminal sequence. Quality control tests for three of the stabilization vector lines (previous to stabilization) assessed viability at all life stages, fertility, adult flight ability, and adult male sexual competitiveness. All three transgenic lines were less fit compared to the wild strain by approximately 5–10% in most tests, however, there was no significant difference in sexual competitiveness which is the major prerequisite for optimal strain release. The second vector, pB[XL-EGFP, Asß2-tub-DsRed.T3], has the DsRed.T3 fluorescent protein reporter gene regulated by the A. suspensa Asß2-tubulin promoter, that resulted in testis and sperm-specific DsRed fluorescence in transgenic male mexflies. Fluorescent sperm bundles were unambiguously observed in the spermathecae of non-transgenic females mated to transgenic males. One transgenic line apparently had a male-specific Y-chromosome insertion, having potential use for sexing by fluorescent-embryo sorting. All transgenic lines expressed easily detectable and stable fluorescence in adults allowing their identification after trapping in the field.