A large-scale survey of genetic copy number variations among Han Chinese residing in Taiwan

Background

Winter migration of immature brown trout (Salmo trutta) into freshwater rivers has been hypothesized to result from physiologically stressful combinations of high salinity and low temperature in the sea.

Results

We sampled brown trout from two Danish populations entering different saline conditions and quantified expression of the hsp70 and Na/K-ATPases α 1b genes following acclimation to freshwater and full-strength seawater at 2°C and 10°C. An interaction effect of low temperature and high salinity on expression of both hsp70 and Na/K-ATPase α 1b was found in trout from the river entering high saline conditions, while a temperature independent up-regulation of both genes in full-strength seawater was found for trout entering marine conditions with lower salinities.

Conclusion

Overall our results support the hypothesis that physiologically stressful conditions in the sea drive sea-run brown trout into freshwater rivers in winter. However, our results also demonstrate intra-specific differences in expression of important stress and osmoregulative genes most likely reflecting adaptive differences between trout populations on a regional scale, thus strongly suggesting local adaptations driven by the local marine environment.     

Induction of plant responses to oviposition and feeding by herbivorous arthropods: a comparison

Plants may respond both to feeding and oviposition by herbivorous insects. While responses of plants to feeding damage by herbivores have been studied intensively during the past decades, only a few, but growing number of studies consider the reactions of plants towards egg deposition by herbivorous insects. Plants showing defensive response to oviposition by herbivores do not `wait' until being damaged by feeding, but may instead react towards one of the initial steps of herbivore attack, the egg deposition. Direct plant defensive responses to feeding act directly against the feeding stages of the herbivores. However, a plant may also show direct defensive responses to egg deposition by (a) formation of neoplasms, (b) formation of necrotic tissue (= hypersensitive response), and (c) production of oviposition deterrents. All these plant reactions have directly negative effects on the eggs, hatching larvae, or on the ovipositing females. Indirect plant defensive responses to feeding result in the emission of volatiles (= synomones) that attract predators or parasitoids of the feeding stages. A few recent studies have shown that plants are able to emit volatiles also in response to egg deposition and that these volatiles attract egg parasitoids. Studies on the mechanisms of induction of synomones by egg deposition show several parallels to the mechanisms of induction of plant responses by feeding damage. When considering induced plant defence against herbivores from an evolutionary point of view, the question arises whether herbivores evolved the ability to circumvent or even to exploit the plant's defensive responses. The reactions of herbivores to oviposition induced plant responses are compared with their reactions to feeding induced plant responses.     

Effects of plant invasions on the species richness of abandoned agricultural land

While exotic plant invasions are thought to lead to declines in native species, the long-term impacts of such invasions on community structure are poorly known. Furthermore, it is unknown how exotic plant invasions compare to invasions by native species. We present data from 40 yr of continuous vegetation sampling of 10 fields released from agriculture to examine the effects of invasions on species richness. The effects of both exotic and native species invasions on species richness were largely driven by variations among fields with most species not significantly affecting species richness. However, invasion and dominance by the exotics Agropyron repens, Lonicera japonica. Rosa multiflora. Trifolium pratense and the native Solidago canadensis were associated with declines in richness. Invasions by exotic and native species during old field succession have similar effects on species richness with dominance by species of either group being associated with loss of species richness. Exotic species invasions tended to have stronger effects on richness than native invasions. No evidence was found of residual effects of invasions because the impact of the invasion disappeared with the decline of the invading population. When pooled across species, heavy invasion by exotic species resulted in greater loss o species richness than invasion by native species. Studies of invasion that utilize multiple sites must account for variability among sites. In our study, had we no included field as a factor we would have incorrectly concluded that invasion consistently resulted in changes in species richness.     

Plant–microbe interactions change along a tallgrass prairie restoration chronosequence

Soil microbial communities are critical in determining the performance and density of species in plant communities. However, their role in regulating the success of restorations is much less clear. This study assessed the ability of soil microbial communities to regulate the growth and performance of two potentially dominant grasses and two common forbs in tallgrass prairie restorations. Specifically, we examined the effects of soil microbial communities along a restoration chronosequence from agricultural fields to remnant prairies using experimentally inoculated soils. The two grass species, Andropogon gerardii and Sorghastrum nutans, grew best with the agricultural inoculates and experienced a decline in performance in later stages of the chronosequence, indicating that the microbial community shifted from being beneficial to grasses in the early stages to inhibiting grasses in the later stages of restoration. Growth of the forb, Silphium terebinthinaceum, varied little with inoculation or position along the restoration chronosequence. Growth of Baptisia leucantha, a legume, appeared limited by nodule formation in agricultural soils, peaked in young restoration soils along with nodule formation, but decreased in older soils as the microbial community became more antagonistic. Overall, negative feedbacks tended to be less important early in restoration, but appeared important in remnant and older restored prairies. Our results provide evidence that it may be advantageous for management practices to take negative soil feedbacks into consideration when trying to recreate the diversity of tallgrass prairies.     

Suramin disrupts the gliotic response following a stab wound injury to the adult rat brain

Reactive gliosis, observed in numerous pathological states, leads to the formation of a glial scar that is believed to impede axonal regeneration. Astrocyte reactivity can be initiated both in vitro and in vivo by various cytokines. Thus, the aim of this study was to investigate if suramin, a polysulfonated napthylurea that has been shown to inhibit the binding of many different cytokines to their cell surface receptors, could attenuate the glial response after brain injury. A single dose of suramin (5 μl, 75 μM) or saline vehicle was injected intracerebrally through the same needle used to make the stab wound at the time of lesioning. Suramin-treated animals showed an obvious reduction in several parameters of CNS inflammation: cellular proliferation, GFAP levels, and tenascin-C immunoreactivity were reduced in suramin-treated as compared to control animals at early time points. GFAP immunoreactivity was strikingly reduced at 3 days after injury, as confirmed by Western blot analysis. This reduction was transient, however, in that the difference in GFAP expression between suramin-treated and control animals was less apparent at 7 days and had disappeared by 30 days after injury. Likewise, fewer BrdU-positive cells were noted in treated versus control tissue at 1 and 3 days, but this difference was not significant by 7 days. Moreover, tenascin immunoreactivity was significantly diminished at 24 h as confirmed by Western blot analysis in suramin-treated lesion areas, which is analogous to our observations that suramin can antagonize tenascin expression by cultured astrocytes treated with bFGF. In addition, examination of the corpus callosum of saline-treated animals 30 days post-trauma revealed a disruption of the fiber tract within the lesion site, while suramin-treated animals displayed numerous fibers spanning the lesion. These results demonstrate that a single injection of suramin transiently inhibits the gliotic response, which may be sufficient to ameliorate subsequent tissue damage.     

Sequence Analysis of Tn10 Insertion Sites in a Collection of Escherichia coli Strains Used for Genetic Mapping and Strain Construction

The chromosomal insertion sites of Tn10-containing Escherichia coli strains were amplified by inverse PCR, and the nucleotide sequences of the junctions were determined. In 95 strains analyzed, 88 unique Tn10 positions were determined and matched to the E. coli chromosome sequence. Two gaps in insertion site positions were noted, one including the terminus of DNA replication and another bounded by recombination hot spots RhsA and RhsB.     

γ-AMINOBUTYRIC ACID RECEPTOR BINDING and UPTAKE IN MEMBRANE FRACTIONS OF CRAYFISH MUSCLE

Abstract— The uptake and binding of [³H]GABA and the binding of [³H]muscimol were measured in cell-free fractions of crayfish muscle. The uptake of GABA was saturable, of high affinity ( K _m= 0.5μ m ), and inhibited by low concentrations of compounds believed to block GABA uptake specifically, such as nipecotic acid and 2,4,diaminobutyric acid. The GABA uptake activity was localized to sucrose gradient fractions enriched in sarcolemma as demonstrated by marker enzymes and electron microscopy. The binding of the potent GABAergic agonist muscimol was also localized to the sarcolemma. The binding was saturable, of high affinity (K _D = 9 n m ), and inhibited by GABA (K ₁ = 125 n m ) and by low concentrations of receptor-specific GABA analogues, such as isoguvacine, imidazole acetic acid, and 3-aminopropane sulfonic acid. The rank order for inhibition by GABA analogues of [³H]muscimol binding sites correlated very well with activity on GABA synapses in invertebrates, consistent with specific postsynaptic receptor labeling.     

Barley aleurone cells contain two types of vacuoles. Characterization Of lytic organelles by use of fluorescent probes

Light microscopy was used to study the structure and function of vacuoles in living protoplasts of barley (Hordeum vulgare cv Himalaya) aleurone. Light microscopy showed that aleurone protoplasts contain two distinct types of vacuole: the protein storage vacuole and a lysosome-like organelle, which we have called the secondary vacuole. Fluorescence microscopy using pH-sensitive fluorescent probes and a fluorogenic substrate for cysteine proteases showed that both protein storage vacuoles and secondary vacuoles are acidic, lytic organelles. Ratio imaging showed that the pH of secondary vacuoles was lower in aleurone protoplasts incubated in gibberellic acid than in those incubated in abscisic acid. Uptake of fluorescent probes into intact, isolated protein storage vacuoles and secondary vacuoles required ATP and occurred via at least two types of vanadate-sensitive, ATP-dependent tonoplast transporters. One transporter catalyzed the accumulation of glutathione-conjugated probes, and another transported probes not conjugated to glutathione.     

IL-33 facilitates rapid expulsion of the parasitic nematode Strongyloides ratti from the intestine via ILC2- and IL-9-driven mast cell activation

Parasitic helminths are sensed by the immune system via tissue-derived alarmins that promote the initiation of the appropriate type 2 immune responses. Here we establish the nuclear alarmin cytokine IL-33 as a non-redundant trigger of specifically IL-9-driven and mast cell-mediated immunity to the intestinal parasite Strongyloides ratti. Blockade of endogenous IL-33 using a helminth-derived IL-33 inhibitor elevated intestinal parasite burdens in the context of reduced mast cell activation while stabilization of endogenous IL-33 or application of recombinant IL-33 reciprocally reduced intestinal parasite burdens and increased mast cell activation. Using gene-deficient mice, we show that application of IL-33 triggered rapid mast cell-mediated expulsion of parasites directly in the intestine, independent of the adaptive immune system, basophils, eosinophils or Gr-1⁺ cells but dependent on functional IL-9 receptor and innate lymphoid cells (ILC). Thereby we connect the described axis of IL-33-mediated ILC2 expansion to the rapid initiation of IL-9-mediated and mast cell-driven intestinal anti-helminth immunity.