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1.
Summary Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) -naphthylphosphate and Fast Blue BB; (4) -glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and -glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, and capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.  相似文献   
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The conservation of unique populations of animals is critical in order to preserve valuable genetic diversity and, where populations are free‐living, maintain their irreplaceable influence upon habitat ecology. An accurate assessment of genetic diversity and structure within and between populations is crucial in order to design and implement conservation strategies in natural and domesticated species. Moreover, where it is possible to identify relic populations that are related to a structured breed an ideal opportunity presents itself to model processes that reveal historical factors that have shaped genetic diversity. The origins of native UK mountain and moorland ponies are uncertain, but they may have directly descended from prehistoric populations and potentially harbour specific adaptations to the uplands of Britain and Ireland. To date, there have been no studies of population structure and genetic diversity present within a free‐living group of ponies in the Carneddau mountain range of North Wales. Herein, we describe the use of microsatellites and SNPs together with analysis of the mitochondrial control region to quantify the extent and magnitude of genetic diversity present in the feral Carneddau pony and relate this to several recognised British and Irish pony breeds. Our results establish that the feral Carneddau ponies represent a unique and distinctive population that merits recognition as a defined population and conservation priority. We discuss the implications for conservation of this population as a unique pool of genetic diversity adapted to the British uplands and potentially of particular value in maintaining the biodiversity of these habitats.  相似文献   
3.
Phage display techniques using random peptide interactions have supported the role of mammalian glutathione transferase (GST) as part of a signalling pathway for both oxidative stress and an apoptosis pathway. Little is known about the interaction of nonmammalian GST with other proteins. GSTs have been implicated in the development of chronic nematode infections by neutralising cytotoxic products arising from host immune initiated reactive oxygen species (ROS) assault. In this study we attached one of the key GSTs expressed in the model nematode Caenorhabditis elegans to an affinity support matrix and directly identified major interacting proteins by two-dimensional electrophoresis and peptide mass fingerprinting before and following oxidative stress. Nematode GST does not appear to be a stand-alone enzyme and interacts with many types of proteins in both normal and ROS stress conditions. Pull-down proteomic presents a flexible, label free, rapid and economical assay without specialised ligand fishing equipment to identify protein binding partners.  相似文献   
4.
Radiocarbon dating, pollen and non-pollen palynomorph analyses from a lake core were used to establish the timing and effects of farming activities around Lake Igaliku, Eastern Settlement, Greenland. The absence of agro-pastoral impact before the medieval colonization by Europeans provides an opportunity to understand the development of farming activity in a pristine landscape. The results show that the first phase of clearance and grazing pressure, without the expansion of the Norse apophyte (native plant, in habitats created by humans) Rumex acetosa type, could have occurred in the 9–10th century a.d. The presence of Norse settlers and livestock is clearly recorded from the 11–12th century a.d. with increasing frequencies of the Norse apophytes Rumex acetosa type and Ranunculus acris type, and coprophilous fungi. This colonization phase is followed by a period of decreasing human impact at the beginning of the 14th century, with a decrease in weeds, apophytes and coprophilous fungi suggesting a reduced grazing pressure. The regrowth of Salix and Betula and the disappearance of anthropogenic indicators except Rumex acetosa type between the 15th and 18th century demonstrate the abandonment of the settlement, until the development of contemporary agriculture in the 20th century.  相似文献   
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Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction.  相似文献   
8.
Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere–atmosphere–climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. We describe the diurnal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were dominated by isoprene, which attained high emission rates of up to 35.4 mg m?2 h?1 at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which highlights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Nevertheless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, confirming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7–17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement campaign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. The megan v2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes during drought events.  相似文献   
9.
Yeast and human Eme1 protein, in complex with Mus81, constitute an endonuclease that cleaves branched DNA structures, especially those arising during stalled DNA replication. We identified mouse Eme1, and show that it interacts with Mus81 to form a complex that preferentially cleaves 3'-flap structures and replication forks rather than Holliday junctions in vitro. We demonstrate that Eme1-/- embryonic stem (ES) cells are hypersensitive to the DNA cross-linking agents mitomycin C and cisplatin, but only mildly sensitive to ionizing radiation, UV radiation and hydroxyurea treatment. Mammalian Eme1 is not required for the resolution of DNA intermediates that arise during homologous recombination processes such as gene targeting, gene conversion and sister chromatid exchange (SCE). Unlike Blm-deficient ES cells, increased SCE was seen only following induced DNA damage in Eme1-deficient cells. Most importantly, Eme1 deficiency led to spontaneous genomic instability. These results reveal that mammalian Eme1 plays a key role in DNA repair and the maintenance of genome integrity.  相似文献   
10.
The oogenesis of the Crustacea Amphipoda Orchestia gammarellus can be divided in five stages taking into consideration both the oocyte ultrastructure and the physiology of the ovary. The primary oogonium (12 μm in diameter) is lodged within the germinative zone: after division, the daughter cell (or secondary oogonium) leaves this area and enters meiotic prophase. Stage I is represented by the oocyte with visible chromosomes (12–18 μm in diameter) the cytoplasmic ultrastructure of which is comparable to that of the oogonium. Stage II or previtellogenesis is characterized by a considerable growth of the oocyte (18–80 μm in diameter) which becomes enriched in ribosomes and vesicles of the rough endoplasmic reticulum; the oocyte does not yet contain any vitelline reserve (proteinaceous and lipid). Stage III or primary vitello-genesis (80–160 μm in diameter) is typified by the synthetic activity of the rough endoplasmic reticulum, corresponding to an endogenous accumulation of proteinaceous yolk. Stage IV or secondary vitellogenesis (160–800 μm in diameter) only appears during the period of reproduction; by means of endocytosis the oocyte accumulates yolk spheres in addition to lipid droplets, the origin of which is uncertain; towards the end of vitellogenesis, cortical granules become a feature that is noted for the first time in Crustacea. The last stage or maturation (800 μm in diameter) starts right before or immediately after the exuviation of the female and ends with fertilization.  相似文献   
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