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21.
Sialylation is a biosynthetic process occurring in the trans compartments
of the Golgi apparatus. Corresponding evidence is based on localization and
biochemical studies of alpha2, 6(N)-sialyltransferase (ST6Gal I) as
previously reported. Here we describe generation and characterization of
polyclonal antibodies to recombinant rat alpha2,3(N)-sialyltransferase
(ST3Gal III) expressed as a soluble enzyme in Sf9 cells or as a
beta-galactosidase-human-ST3Gal III fusion- protein from E.coli ,
respectively. These antibodies were used to localize ST3Gal III by
immunofluorescence in various cell lines and rat kidney tissue sections. In
transiently transfected COS cells the antibodies directed to soluble
sialyltransferase or the sialyltransferase portion of the fusion-protein
only recognized the recombinant antigen retained in the endoplasmic
reticulum. However, an antibody fraction crossreactive with
beta-galactosidase recognized natively expressed ST3Gal III which was found
to be colocalized with beta1, 4-galactosyltransferase in the Golgi
apparatus of several cultured cell lines. Antibodies affinity purified on
the beta- galactosidase-ST3Gal III fusion-protein column derived from both
antisera have then been used to localize the enzyme in perfusion-fixed rat
kidney sections. We found strong staining of the Golgi apparatus of tubular
epithelia and a brush-border-associated staining which colocalized with
cytochemical staining of the H+ATPase. This subcellular localization was
not observed for ST6Gal I which localized to the Golgi apparatus. These
data show colocalization in the Golgi apparatus and different post-Golgi
distributions of the two sialyltransferases.
相似文献
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EG Ciolac SS Mantuani CM Neiva CEL Verardi DM Pess?a-Filho L Pimenta 《Biology of sport / Institute of Sport》2015,32(2):103-108
The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h−1; RPE: 5.7±1.3 km · h−1) and high-intensity intervals (HR: 7.8±1.9 km · h−1; RPE: 8.2±1.7 km · h−1) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects. 相似文献
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Remo Freimann Helmut Bürgmann Stuart EG Findlay Christopher T Robinson 《The ISME journal》2013,7(12):2361-2373
Glaciated alpine floodplains are responding quickly to climate change through shrinking ice masses. Given the expected future changes in their physicochemical environment, we anticipated variable shifts in structure and ecosystem functioning of hyporheic microbial communities in proglacial alpine streams, depending on present community characteristics and landscape structures. We examined microbial structure and functioning during different hydrologic periods in glacial (kryal) streams and, as contrasting systems, groundwater-fed (krenal) streams. Three catchments were chosen to cover an array of landscape features, including interconnected lakes, differences in local geology and degree of deglaciation. Community structure was assessed by automated ribosomal intergenic spacer analysis and microbial function by potential enzyme activities. We found each catchment to contain a distinct bacterial community structure and different degrees of separation in structure and functioning that were linked to the physicochemical properties of the waters within each catchment. Bacterial communities showed high functional plasticity, although achieved by different strategies in each system. Typical kryal communities showed a strong linkage of structure and function that indicated a major prevalence of specialists, whereas krenal sediments were dominated by generalists. With the rapid retreat of glaciers and therefore altered ecohydrological characteristics, lotic microbial structure and functioning are likely to change substantially in proglacial floodplains in the future. The trajectory of these changes will vary depending on contemporary bacterial community characteristics and landscape structures that ultimately determine the sustainability of ecosystem functioning. 相似文献
27.
The planktonic glaucothoe of the Indo-West Pacific hermit crab Paguropsis typica Henderson has an aberrant anthozoan polyp, identified as a nynanthean actinian, attached to the underside of its thorax. The morphology of the anemone is described. The scapus is dumb-bell shaped and exhibits a slit-like mouth opening oriented transverse to the animal's siphonoglyphal plane. The gonads are very well developed, whereas tentacle-like structures or retractor muscles of certain septa are reduced. In the adult stage, Paguropsis typica is associated with the zoanthidean Epizoanthus paguropsides . It is assumed that the actinian is lost at the ecdysis leading to the first "hermit stage" and that P. typica might possibly seize a free Epizoanthus colony and adapt it to its body. 相似文献
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Sanja Perovic Jürgen Seack Vera Gamulin Werner EG Müller Heinz C Schröder 《BMC cell biology》2001,2(1):7-9