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781.
David A. Pike Jonathan K. Webb Richard Shine 《Ecological Management & Restoration》2011,12(2):110-118
Summary In many ecosystems, increases in vegetation density and the resulting closure of forest canopies are threatening the viability of species that depend upon open, sunlight‐exposed habitats. Consequently, we need to develop management strategies that recreate open habitats while minimizing the impacts on non‐target areas. Selective logging creates canopy gaps, but may result in undesirable effects in other respects. Thus, chainsaws have not been a popular tool for conservation. We conducted a landscape‐scale experiment to test whether selective tree removal can restore patch‐level habitat quality for Australia’s most endangered snake (Hoplocephalus bungaroides) and its main prey (the lizard Oedura lesueurii). We selectively removed canopy trees surrounding 25 overgrown rock outcrops and compared the resultant habitat structure and abiotic conditions to 30 overgrown, shady outcrops and 20 open, sunny outcrops. Removing vegetation decreased canopy cover by 19% in experimental plots and increased incident radiation and thermal regimes. These changes increased the availability of suitable shelter sites for our target species by 131%. At the landscape scale, our manipulations had a trivial effect on forest habitat; by increasing the area of sun‐exposed outcrops, we decreased forest cover by <0.1%. Our results show that targeted canopy removal can increase the availability of sun‐exposed habitat patches for endangered species in biologically meaningful ways. Thus, selective tree felling may be an effective conservation tool for open‐habitat specialists threatened by vegetation overgrowth. 相似文献
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783.
We examined the arrangement and development of identified neurons in zebrafish embryos homozygous for the mutation spt-1, which acts autonomously and specifically to alter the development of precursors of trunk segmented mesoderm, resulting in muscle-deficient myotomes. We found that the mutation alters the morphology, number, and arrangement of identified motoneurons. By transplanting identified motoneurons between wild-type and mutant embryos, we found that the effect of the mutation was nonautonomous. We suggest that the segmental arrangement and proper axonal development of motoneurons may result from interactions with segmented mesoderm. 相似文献
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785.
20 beta-Hydroxy-5 alpha-pregnan-3-one and 20 alpha-hydroxy-5 alpha-pregnan-3-one were isolated and identified from a pool of urine collected from women in the third trimester of pregnancy. Following isolation by Sephadex LH-20 and HPLC, the identity of each compound was established by comparison of GC-MS data for the methyloxime-trimethylsilyl ethers with those for authentic standards. 相似文献
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787.
Rocco Adiutori Johan Aarum Irene Zubiri Michael Bremang Stephan Jung Denise Sheer Ian Pike Andrea Malaspina 《Biochemistry and Biophysics Reports》2018
Protein aggregation in biofluids is a poorly understood phenomenon. Under normal physiological conditions, fluid-borne aggregates may contain plasma or cell proteins prone to aggregation. Recent observations suggest that neurofilaments (Nf), the building blocks of neurons and a biomarker of neurodegeneration, are included in high molecular weight complexes in circulation. The composition of these Nf-containing hetero-aggregates (NCH) may change in systemic or organ-specific pathologies, providing the basis to develop novel disease biomarkers. We have tested ultracentrifugation (UC) and a commercially available protein aggregate binder, Seprion PAD-Beads (SEP), for the enrichment of NCH from plasma of healthy individuals, and then characterised the Nf content of the aggregate fractions using gel electrophoresis and their proteome by mass spectrometry (MS). Western blot analysis of fractions obtained by UC showed that among Nf isoforms, neurofilament heavy chain (NfH) was found within SDS-stable high molecular weight aggregates. Shotgun proteomics of aggregates obtained with both extraction techniques identified mostly cell structural and to a lesser extent extra-cellular matrix proteins, while functional analysis revealed pathways involved in inflammatory response, phagosome and prion-like protein behaviour. UC aggregates were specifically enriched with proteins involved in endocrine, metabolic and cell-signalling regulation. We describe the proteome of neurofilament-containing aggregates isolated from healthy individuals biofluids using different extraction methods. 相似文献
788.
Cobra venom cardiotoxin was found to stimulate the phosphatidylinositol kinase activity present in A431 cell membranes and in detergent extracts of these membranes. Incubation of highly purified phosphatidylinositol 4-kinase from this source with cardiotoxin resulted in a 2- to 3-fold stimulation of phosphatidylinositol kinase activity. The activation of the purified phosphatidylinositol 4-kinase by cardiotoxin was time- and dose-dependent and appeared to be associated with a decrease in the Km apparent of the enzyme for phosphatidylinositol with no change in the Vmax apparent of the enzyme. The data suggest that the phosphatidylinositol 4-kinase is activated by direct interaction of the enzyme with cobra venom cardiotoxin. 相似文献