Cavity type influences abundance of nest-dwelling avian blow flies: an experiment with tree swallows

1. Diverse assemblages of blood-feeding parasitic arthropods occupy the nests of birds, and nest temperature and humidity can strongly influence the population dynamics of these ectoparasites, with important implications for parasite–host relationships. 2. This study used two types of nest box that differed in internal microclimates, one constructed of plywood and the other constructed of boles of aspen (Populus tremuloides Michx.), more closely replicating natural cavities, to examine how nest microclimate affects the prevalence and abundance of nest-dwelling larval blow flies (Protocalliphora and Trypocalliphora spp.) in nests of tree swallows (Tachycineta bicolor Vieillot, 1808). 3. Based on known microclimatic differences between the box types and responses of larval blow flies to different temperatures, it was predicted that the microclimate of plywood boxes would be more favourable for growth and development of larval blow flies, and therefore have higher abundance, and possibly higher prevalence, of larval blow flies. 4. Plywood nest boxes had higher abundance, but not prevalence, of larval blow flies compared with aspen boxes at two different geographical locations in Canada. Nest composition also differed between box types, particularly at one site, where aspen boxes contained more nesting material (grass and feathers) than did plywood boxes. 5. Although it seems probable that microclimate was driving the differences between box types in abundance of larval blow flies, several additional explanations are discussed. These findings may have implications for conservation efforts, particularly those where nest boxes are used to aid in the recovery of declining bird populations.     

Data partitions, Bayesian analysis and phylogeny of the zygomycetous fungal family Mortierellaceae, inferred from nuclear ribosomal DNA sequences

Although the fungal order Mortierellales constitutes one of the largest classical groups of Zygomycota, its phylogeny is poorly understood and no modern taxonomic revision is currently available. In the present study, 90 type and reference strains were used to infer a comprehensive phylogeny of Mortierellales from the sequence data of the complete ITS region and the LSU and SSU genes with a special attention to the monophyly of the genus Mortierella. Out of 15 alternative partitioning strategies compared on the basis of Bayes factors, the one with the highest number of partitions was found optimal (with mixture models yielding the best likelihood and tree length values), implying a higher complexity of evolutionary patterns in the ribosomal genes than generally recognized. Modeling the ITS1, 5.8S, and ITS2, loci separately improved model fit significantly as compared to treating all as one and the same partition. Further, within-partition mixture models suggests that not only the SSU, LSU and ITS regions evolve under qualitatively and/or quantitatively different constraints, but that significant heterogeneity can be found within these loci also. The phylogenetic analysis indicated that the genus Mortierella is paraphyletic with respect to the genera Dissophora, Gamsiella and Lobosporangium and the resulting phylogeny contradict previous, morphology-based sectional classification of Mortierella. Based on tree structure and phenotypic traits, we recognize 12 major clades, for which we attempt to summarize phenotypic similarities. M. longicollis is closely related to the outgroup taxon Rhizopus oryzae, suggesting that it belongs to the Mucorales. Our results demonstrate that traits used in previous classifications of the Mortierellales are highly homoplastic and that the Mortierellales is in a need of a reclassification, where new, phylogenetically informative phenotypic traits should be identified, with molecular phylogenies playing a decisive role.     

Age-related changes in the distribution and frequency of myeloid and T cell populations in the small intestine of calves

Mucosal dendritic cells (DCs) play a key role in discriminating between dietary antigens, commensal microflora and pathogens but little is known regarding age-related changes in mucosal DC populations. We analyzed lymphoid and myeloid populations within the epithelium and lamina propria (LP) of the ileum and jejunum of weaned calves (6 months old) and compared their frequency and distribution with newborn calves (3–5 weeks old). CD4, CD8 and γδ TcR T cells and CD11c^HiMHC Class II⁺ myeloid cell frequency were significantly different when comparing ileum and jejunum of weaned calves. In particular, the number of CD8 and γδ TcR T cells, and CD11c^HiCD14⁺ macrophages was significantly greater in the ileum but CD11c⁺ and CD11b⁺ myeloid cell distribution was similar throughout the mucosal epithelium of the small intestine. Furthermore, significant age-related changes were apparent when comparing the frequency and abundance of mucosal leukocyte subpopulations in newborn and weaned calves. Total mucosal leukocytes (CD45⁺) increased significantly with age in both ileum and jejunum and much of this increase was attributed to mucosal T cells (CD3⁺). In particular, CD4 T cells and NK cells increased significantly in the jejunum and CD8, and γδ TcR T cells increased significantly with age throughout the small intestine. In contrast, CD11c^HiMHC Class II⁺ myeloid cells remained numerically unchanged with age but DCs (CD13⁺, CD26⁺, CD205⁺) were enriched and macrophages (CD14⁺, CD172a⁺) were depleted in older animals. Therefore, regional differences between ileal and jejunal mucosal leukocytes changed with age and there was also a marked age-dependent change in the composition of mucosal myeloid cells. These observations have significant implications for host responses to both pathogens and commensal microflora.     

B-cell activating factor (BAFF) promotes CpG ODN-induced B cell activation and proliferation

It is controversial whether naïve B cells are directly activated in response to TLR9 ligand, CpG ODN. Although bovine blood-derived CD21⁺ B cells express TLR9 and proliferate in response to CpG in mixed-cell populations, purified bovine B cells do not proliferate significantly in response to CpG ODN, even when the B cell receptor is engaged. When co-cultured with CD14⁺ myeloid cells and/or B-cell activating factor (BAFF), a cytokine produced by activated myeloid cells, there was a significant increase in CpG-specific B cell proliferation, and the number of large B cells in general or positive for CD25, all of which are markers for B cell activation. These data suggest that activated myeloid cells and BAFF prime B cells for significant CpG-specific activation. Understanding the signals required to mediate efficient CpG-induced, antigen-independent and T-cell independent activation of B cells has implications for polyclonal B cell activation and the development of autoimmune diseases.     

ProADD: A database on Protein Aggregation Diseases

ProADD, a database for protein aggregation diseases, is developed to organize the data under a single platform to facilitate easy access for researchers. Diseases caused due to protein aggregation and the proteins involved in each of these diseases are integrated. The database helps in classification of proteins involved in the protein aggregation diseases based on sequence and structural analysis. Analysis of proteins can be done to mine patterns prevailing among the aggregating proteins.

Availability

http://bicmku.in/ProADD     

Spectral sensitivity and Color Vision in the Bottlenose Dolphin (Tursiops Truncatus)

Spectral sensitivity was measured in air in a bottlenose dolphin using a behavioral training technique. The spectral sensitivity curve shows two maxima in sensitivity, one in the near ultraviolet part of the spectrum and the other one in the bluegreen part at about 490 nm. Two wavelength discrimination tasks showed that the dolphin could discriminate two wavelengths from the peak regions of the two maxima of the spectral sensitivity function, but not between two wavelengths lying within the broad maximum of the curve in the bluegreen part of the spectrum. Possible underlying mechanisms for the shape of the function are discussed.     

Methyl Salicylate Production and Jasmonate Signaling Are Not Essential for Systemic Acquired Resistance in Arabidopsis

Systemic acquired resistance (SAR) develops in response to local microbial leaf inoculation and renders the whole plant more resistant to subsequent pathogen infection. Accumulation of salicylic acid (SA) in noninfected plant parts is required for SAR, and methyl salicylate (MeSA) and jasmonate (JA) are proposed to have critical roles during SAR long-distance signaling from inoculated to distant leaves. Here, we address the significance of MeSA and JA during SAR development in Arabidopsis thaliana. MeSA production increases in leaves inoculated with the SAR-inducing bacterial pathogen Pseudomonas syringae; however, most MeSA is emitted into the atmosphere, and only small amounts are retained. We show that in several Arabidopsis defense mutants, the abilities to produce MeSA and to establish SAR do not coincide. T-DNA insertion lines defective in expression of a pathogen-responsive SA methyltransferase gene are completely devoid of induced MeSA production but increase systemic SA levels and develop SAR upon local P. syringae inoculation. Therefore, MeSA is dispensable for SAR in Arabidopsis, and SA accumulation in distant leaves appears to occur by de novo synthesis via isochorismate synthase. We show that MeSA production induced by P. syringae depends on the JA pathway but that JA biosynthesis or downstream signaling is not required for SAR. In compatible interactions, MeSA production depends on the P. syringae virulence factor coronatine, suggesting that the phytopathogen uses coronatine-mediated volatilization of MeSA from leaves to attenuate the SA-based defense pathway.     

Panta rhei (QAlign2): an open graphical environment for sequence analysis

MOTIVATION: The first version of the graphical multiple sequence alignment environment QAlign was published in 2003. Heavy response from the molecular-biological user community clearly demonstrated the need for such a platform. RESULTS: Panta rhei extends QAlign by several features. Major redesigns on the user interface, for instance, allow users to flexibily compose views for multiple projects. The new sequence viewer handles datasets with arbitrarily many and arbitrarily large sequences that may still be edited by guided block moving. More distance-based algorithms are available to interactively reconstruct phylogenetic trees which can now also be zoomed and navigated graphicaly. AVAILABILITY: Executables and the JAVA source code are available under the Apache license at http://gi.cebitec.uni-bielefeld.de/qalign CONTACT: qalign@cebitec.uni-bielefeld.de.     

Transition of healthy to diseased synovial tissue in rheumatoid arthritis is associated with gain of mesenchymal/fibrotic characteristics

The healthy synovial lining layer consists of a single cell layer that regulates the transport between the joint cavity and the surrounding tissue. It has been suggested that abnormalities such as somatic mutations in the p53 tumor-suppressor gene contribute to synovial hyperplasia and invasion in rheumatoid arthritis (RA). In this study, expression of epithelial markers on healthy and diseased synovial lining tissue was examined. In addition, we investigated whether a regulated process, resembling epithelial to mesenchymal transition (EMT)/fibrosis, could be responsible for the altered phenotype of the synovial lining layer in RA. Synovial tissue from healthy subjects and RA patients was obtained during arthroscopy. To detect signs of EMT, expression of E-cadherin (epithelial marker), collagen type IV (indicator of the presence of a basement membrane) and alpha-smooth muscle actin (alpha-sma; a myofibroblast marker) was investigated on frozen tissue sections using immunohistochemistry. Fibroblast-like synoviocytes (FLSs) from healthy subjects were isolated and subjected to stimulation with synovial fluid (SF) from two RA patients and to transforming growth factor (TGF)-beta. To detect whether EMT/fibrotic markers were increased, expression of collagen type I, alpha-sma and telopeptide lysylhydroxylase (TLH) was measured by real time PCR. Expression of E-cadherin and collagen type IV was found in healthy and arthritic synovial tissue. Expression of alpha-sma was only found in the synovial lining layer of RA patients. Stimulation of healthy FLSs with SF resulted in an upregulation of alpha-sma and TLH mRNA. Collagen type I and TLH mRNA were upregulated after stimulation with TGF-beta. Addition of bone morphogenetic protein (BMP)-7 to healthy FLS stimulated with SF inhibited the expression of alpha-sma mRNA. The finding that E-cadherin and collagen type IV are expressed in the lining layer of healthy and arthritic synovium indicates that these lining cells display an epithelial-like phenotype. In addition, the presence of alpha-sma in the synovial lining layer of RA patients and induction of fibrotic markers in healthy FLSs by SF from RA patients indicate that a regulated process comparable to EMT might cause the alteration in phenotype of RA FLSs. Therefore, BMP-7 may represent a promising agent to counteract the transition imposed on synoviocytes in the RA joint.