Cool,cold or colder? Spatial segregation of prions and blue petrels is explained by differences in preferred sea surface temperatures

The Southern Ocean provides one of the largest environmental gradients on Earth that lacks geographical barriers, and small but highly mobile petrels living there may offer fine models of evolution of diversity along environmental gradients. Using geolocation devices, we investigated the winter distribution of closely related petrel species breeding sympatrically in the southern Indian Ocean, and applied ecological niche models to compare environmental conditions in the habitat used. We show that thin-billed prions (Pachyptila belcheri), Antarctic prions (Pachyptila desolata) and blue petrels (Halobaena caerulea) from the Kerguelen archipelago in the southern Indian Ocean segregate latitudinally, sea surface temperature being the most important variable separating the distribution of the species. Antarctic prions spent the winter north of the Polar Front in temperate waters, whereas blue petrels were found south of the Polar Front in Antarctic waters. Thin-billed prions preferred intermediate latitudes and temperatures. Stable isotope values of feathers reflected this near complete niche separation across an ecological gradient that spans large scales, and suggest evolutionary isolation by environment. In pelagic seabirds that exploit large areas of ocean, spatial niche partitioning may not only facilitate coexistence among ecologically similar species, but may also have driven their evolution in the absence of geographical barriers.     

Do not neglect surroundings in restoration of disturbed sites

We examined the influence of surroundings, i.e. proximity effects, on the course of spontaneous vegetation succession using two data sets. In the first data set, we tested the effects of surrounding vegetation (woodlands, wetlands, grasslands, and synanthropic) on succession in various disturbed habitats in the Czech Republic by comparing successional sites with more natural vegetation within 100 m and at 1 km from each site. The habitats included old fields, gravel‐sand pits, spoil heaps from black coal mining, industrially extracted peatlands, and acidic stone quarries. We found that, with the exception of wetlands, the influence of the vegetation types on seral vegetation was nearly always significant using marginal and partial Canonical Correspondence Analyses. In the second data set, which included 27 limestone quarries, we compared species lists outside (up to 100 m apart) and inside the quarries using Detrended Correspondence Analysis and the Sørensen similarity index. We found much higher species similarity between outside and inside particular limestone quarries than among the quarries themselves and among their surroundings, which also indicates that the seral vegetation is decisively influenced by the surroundings. We argue that restoration ecologists should carefully consider the nature of the surroundings of disturbed sites because of its profound impact on restoration processes. They should conduct inventories and prescribe some restoration measures not only inside a restored site, but also in its surroundings.     

Hay-bait traps are a useful tool for sampling of soil dwelling millipedes and centipedes

Some species of centipedes and millipedes inhabit upper soil layers exclusively and are not recorded by pitfall trapping. Because of their sensitivity to soil conditions, they can be sampled quantitatively for evaluation of soil conditions. Soil samples are heavy to transport and their processing is time consuming, and such sampling leads to disturbance of the soil surface which land-owners do not like. We evaluated the use of hay-bait traps to sample soil dwelling millipedes and centipedes. The effectiveness of this method was found to be similar to the effectiveness of soil sampling. Hay-bait traps installed for 8–10 weeks can substitute for direct soil sampling in ecological and inventory studies.     

Regulatory MicroRNA Networks:Complex Patterns of Target Pathways for Disease-related and Housekeeping MicroRNAs

Blood-based micro RNA(mi RNA) signatures as biomarkers have been reported for various pathologies, including cancer, neurological disorders, cardiovascular diseases, and also infections. The regulatory mechanism behind respective mi RNA patterns is only partially understood. Moreover, ‘‘preserved' mi RNAs, i.e., mi RNAs that are not dysregulated in any disease,and their biological impact have been explored to a very limited extent. We set out to systematically determine their role in regulatory networks by defining groups of highly-dysregulated mi RNAs that contribute to a disease signature as opposed to preserved housekeeping mi RNAs. We further determined preferential targets and pathways of both dysregulated and preserved mi RNAs by computing multi-layer networks, which were compared between housekeeping and dysregulated mi RNAs. Of 848 mi RNAs examined across 1049 blood samples, 8 potential housekeepers showed very limited expression variations, while 20 mi RNAs showed highly-dysregulated expression throughout the investigated blood samples. Our approach provides important insights into mi RNAs and their role in regulatory networks. The methodology can be applied to systematically investigate the differences in target genes and pathways of arbitrary mi RNA sets.     

The role of glycine residues 140 and 141 of subunit B in the functional ubiquinone binding site of the Na+-pumping NADH:quinone oxidoreductase from Vibrio cholerae

The Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) is the main entrance for electrons into the respiratory chain of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone, and the free energy released by this redox reaction is used to create an electrochemical gradient of sodium across the cell membrane. Here we report the role of glycine 140 and glycine 141 of the NqrB subunit in the functional binding of ubiquinone. Mutations at these residues altered the affinity of the enzyme for ubiquinol. Moreover, mutations in residue NqrB-G140 almost completely abolished the electron transfer to ubiquinone. Thus, NqrB-G140 and -G141 are critical for the binding and reaction of Na(+)-NQR with its electron acceptor, ubiquinone.     

Basigin interacts with both MCT1 and MCT2 in murine spermatozoa

Lactate is provided to spermatogenic cells by Sertoli cells as an energy substrate and its transport is regulated by H(+)-monocarboxylate co-transporters (MCTs). In the case of several cell types it is known that MCT1 is associated with basigin and MCT2 with embigin. Here we demonstrate co-localization and co-immunoprecipitation of basigin with both MCT1 and MCT2 in sperm, whereas no interaction with embigin was detectable. An investigation of the functional activity of MCT proteins revealed that it was mainly the application of L-lactate which resulted in a decrease in pH(i) . The pH(i) changes were blocked with α-cyano-4-OH cinnamate and the preference for L-lactate-as opposed to D-Lactate-was demonstrated by the determination of ATP after exposure to both lactate isomers. We propose that basigin interacts with MCT1 and MCT2 to locate them properly in the membrane of spermatogenic cells and that this may enable sperm to utilize lactate as an energy substrate contributing to cell survival.     

The transient receptor potential channel TRPV6 is dynamically expressed in bone cells but is not crucial for bone mineralization in mice

Bone is the major store for Ca(2+) in the body and plays an important role in Ca(2+) homeostasis. During bone formation and resorption Ca(2+) must be transported to and from bone by osteoblasts and osteoclasts, respectively. However, little is known about the Ca(2+) transport machinery in these bone cells. In this study, we examined the epithelial Ca(2+) channel TRPV6 in bone. TRPV6 mRNA is expressed in human and mouse osteoblast-like cells as well as in peripheral blood mononuclear cell-derived human osteoclasts and murine tibial bone marrow-derived osteoclasts. Also other transcellular Ca(2+) transport genes, calbindin-D(9k) and/or -D(28K), Na(+)/Ca(2+) exchanger 1, and plasma membrane Ca(2+) ATPase (PMCA1b) were expressed in these bone cell types. Immunofluorescence and confocal microscopy on human osteoblasts and osteoclasts and mouse osteoclasts revealed TRPV6 protein at the apical domain and PMCA1b at the osteoidal domain of osteoblasts, whereas in osteoclasts TRPV6 was predominantly found at the bone-facing site. TRPV6 was dynamically expressed in human osteoblasts, showing maximal expression during mineralization of the extracellular matrix. 1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) did not change TRPV6 expression in both mineralizing and non-mineralizing SV-HFO cultures. Lentiviral transduction-mediated overexpression of TRPV6 in these cells did not alter mineralization. Bone microarchitecture and mineralization were unaffected in Trpv6(D541A/D541A) mice in which aspartate 541 in the pore region was replaced with alanine to render TRPV6 channels non-functional. In summary, TRPV6 and other proteins involved in transcellular Ca(2+) transport are dynamically expressed in bone cells, while TRPV6 appears not crucial for bone metabolism and matrix mineralization in mice.     

Induction of type I IFN is a physiological immune reaction to apoptotic cell-derived membrane microparticles

Membrane microparticles (MMP) released from apoptotic cells deliver signals that secure the anti-inflammatory response beyond the nearest proximity of the apoptotic cell. Plasmacytoid dendritic cells (pDC) are sentinels prepared to detect cellular processes that endanger the organism. They play a key role in the regulation of both pro- and anti-inflammatory immune responses. Based on the assumption that pDC could participate in the initiation of the anti-inflammatory response to apoptotic cells, we investigated the effects of apoptotic cell-derived MMP on human pDC. The results obtained in our experiments confirmed that MMP released from apoptotic cells trigger IFN-α secretion from human pDC. They further suggest that pDC activation results from sensing of DNA contained in MMP. MMP-DNA displays a particularly strong stimulatory activity compared with MMP-RNA and other sources of DNA. Inhibition of MMP-induced IFN-α secretion by cytochalasin D, chloroquine, and an inhibitory G-rich oligodeoxynucleotide identify TLR9 as the receptor for MMP-DNA. In marked contrast to the pDC response in autoimmune patients, in healthy subjects MMP-mediated stimulation of pDC-derived IFN-α was found to be independent of FcγRIIA (CD32A). Based on our findings, we conclude that induction of pDC-derived IFN-α by MMP is a physiological event; future investigations are necessary to elucidate whether pDC activation promotes inflammation or propagates tolerance in the context of apoptotic cell clearance.