Specificity of the collagenolytic enzyme from the fungus Entomophthora coronata: comparison with the bacterial collagenase from Achromobacter iophagus.

The specificity of the collagenolytic enzyme from the fungus Entomophthora coronata toward some inhibitors and the B chain of oxidized insulin was investigated and compared to that of the bacterial collagenase from Achromobacter iophagus. The fungal enzyme was completely inhibited by diisopropylfluorophosphate, tosyl-l-lysine chloromethyl ketone, and tosyl-amino-2-phenylethyl chloromethyl ketone but not at all by ethylenediaminetetraacetate. This indicates that it is not a metalloenzyme like the bacterial Achromobacter collagenase. The B chain of insulin was not hydrolysed at all by the bacterial enzyme under conditions where extensive digestion was observed with the Entomophthora enzyme. The fungal enzyme cleaves preferentially the bonds $\text{Leu}\text{15}\text{-}\text{Tyr}\text{16}\text{and}\text{Leu}\text{11}\text{Val}\text{12}$ as determined by automatic sequencing; the secondary cleavages were identified by a systematic analysis of the digestion mixture; thus, the fungal collagenolytic enzyme from Entomophthora coronata differs both structurally and functionally from the bacterial Achromobacter collagenase.     

Presynaptic CK2 promotes synapse organization and stability by targeting Ankyrin2

The precise regulation of synapse maintenance is critical to the development and function of neuronal circuits. Using an in vivo RNAi screen targeting the Drosophila kinome and phosphatome, we identify 11 kinases and phosphatases controlling synapse stability by regulating cytoskeletal, phospholipid, or metabolic signaling. We focus on casein kinase 2 (CK2) and demonstrate that the regulatory (β) and catalytic (α) subunits of CK2 are essential for synapse maintenance. CK2α kinase activity is required in the presynaptic motoneuron, and its interaction with CK2β, mediated cooperatively by two N-terminal residues of CK2α, is essential for CK2 holoenzyme complex stability and function in vivo. Using genetic and biochemical approaches we identify Ankyrin2 as a key presynaptic target of CK2 to maintain synapse stability. In addition, CK2 activity controls the subcellular organization of individual synaptic release sites within the presynaptic nerve terminal. Our study identifies phosphorylation of structural synaptic components as a compelling mechanism to actively control the development and longevity of synaptic connections.     

Preadapted for invasiveness: do species traits or their plastic response to shading differ between invasive and non‐invasive plant species in their native range?

Aim Species capable of vigorous growth under a wide range of environmental conditions should have a higher chance of becoming invasive after introduction into new regions. High performance across environments can be achieved either by constitutively expressed traits that allow for high resource uptake under different environmental conditions or by adaptive plasticity of traits. Here we test whether invasive and non‐invasive species differ in presumably adaptive plasticity. Location Europe (for native species); the rest of the world and North America in particular (for alien species). Methods We selected 14 congeneric pairs of European herbaceous species that have all been introduced elsewhere. One species of each pair is highly invasive elsewhere in the world, particularly so in North America, whereas the other species has not become invasive or has spread only to a limited degree. We grew native plant material of the 28 species under shaded and non‐shaded conditions in a common garden experiment, and measured biomass production and morphological traits that are frequently related to shade tolerance and avoidance. Results Invasive species had higher shoot–root ratios, tended to have longer leaf‐blades, and produced more biomass than congeneric non‐invasive species both under shaded and non‐shaded conditions. Plants responded to shading by increasing shoot–root ratios and specific leaf area. Surprisingly, these shade‐induced responses, which are widely considered to be adaptive, did not differ between invasive and non‐invasive species. Main conclusions We conclude that high biomass production across different light environments pre‐adapts species to become invasive, and that this is not mediated by plasticities of the morphological traits that we measured.     

Structure of isolated sensilla and sensory neurons in vitro: Observations on developing silkmoth antennae

Summary By combined enzymatic and mechanical treatment, it was possible to dissociate the sensory epithelium of developing antennae of male Antheraea polyphemus and A. pernyi silkmoths from the stage of separation of the antennal branches up to the early stages of cuticle deposition. Large numbers of entire developing trichoid sensilla were isolated. These are characterized by a large trichogen cell with a long apical, hair-forming process and a large nucleus. A cluster of 2–3 sensory neurons, enclosed by the thecogen cell, is situated in the basal region. The dendrites run past the nucleus of the trichogen cell into the apical process from which they protrude laterally. The nuclei of the tormogen and a 4^th enveloping cell can be distinguished near the base of the prospective hair. After further dissociation, only the neuron clusters remain, still enclosed by their thecogen cell and often attached to the antennal branch nerve via their axons. It is finally possible to disrupt the thecogen cells and the axons, leaving the sensory neurons with inner dendritic segments and axon stumps. The majority of these neurons can be expected to be olfactory.     

Both wound-inducible and tuber-specific expression are mediated by the promoter of a single member of the potato proteinase inhibitor II gene family

A chimeric gene consisting of 1.3 kb of the 5' regulatory region of a member of the potato proteinase inhibitor II gene family, the coding region of the bacterial β-glucuronidase (GUS) gene and 260 bp of the proteinase inhibitor II 3'-untranslated region containing the poly(A) addition site was introduced into potato and tobacco by Agrobacterium tumefaciens mediated transformation. Analysis of transgenic plants demonstrates systemic, wound-inducible expression of this gene in stem and leaves of potato and tobacco. Constitutive expression was found in stolons and tubers of non-wounded potato plants. Histochemical experiments based on the enzymatic activity of the GUS protein indicate an association of the proteinase inhibitor II promoter activity with vascular tissue in wounded as well as in systemically induced non-wounded leaves, petioles, potato stems and in developing tubers. These data prove that one single member of the proteinase inhibitor II gene family contains cis-active elements, which are able to respond to both developmental and environmental signals. Furthermore they support the hypothesis of an inducing signal (previously called proteinase inhibitor inducing factor), which is released at the wound site and subsequently transported to non-wounded parts of the plant via the vascular system from where it is released to the surrounding tissue.