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51.
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54.
Glycosylation sites and site-specific glycosylation in human Tamm- Horsfall glycoprotein 总被引:4,自引:1,他引:3
The N-glycosylation sites of human Tamm-Horsfall glycoprotein from one
healthy male donor have been characterized, based on an approach using
endoproteinase Glu-C (V-8 protease, Staphylococcus aureus ) digestion and a
combination of chromatographic techniques, automated Edman sequencing, and
fast atom bombardment mass spectrometry. Seven out of the eight potential
N-glycosylation sites, namely, Asn52, Asn56, Asn208, Asn251, Asn298,
Asn372, and Asn489, turned out to be glycosylated, and the potential
glycosylation site at Asn14, being close to the N-terminus, is not used.
The carbohydrate microheterogeneity on three of the glycosylation sites was
studied in more detail by high-pH anion-exchange chromatographic profiling
and 500 MHz1H-NMR spectroscopy. Glycosylation site Asn489 contains mainly
di- and tri-charged oligosaccharides which comprise, among others, the
GalNAc4 S (beta1-4)GlcNAc terminal sequence. Only glycosylation site Asn251
bears oligomannose-type carbohydrate chains ranging from Man5GlcNAc2to
Man8GlcNAc2, in addition to a small amount of complex- type structures.
Profiling of the carbohydrate moieties of Asn208 indicates a large
heterogeneity, similar to that established for native human Tamm-Horsfall
glycoprotein, namely, multiply charged complex-type carbohydrate
structures, terminated by sulfate groups, sialic acid residues, and/or the
Sda-determinant.
相似文献
55.
B Kornmatitsuk E Dahl E Ropstad JF Beckers H Gustafsson H Kindahl 《Acta veterinaria Scandinavica》2004,45(1):47
The high incidence of stillbirth in Swedish Holstein heifers has increased continuously during the last 15 years to an average
of 11% today. The pathological reasons behind the increased incidence of stillbirth are unknown. The present experiment was
undertaken to investigate possible causes of stillbirth and to study possible physiological markers for predicting stillbirth.
Twenty Swedish Holstein dairy heifers sired by bulls with breeding values for a high risk of stillbirth (n = 12) (experimental
group) and a low risk of stillbirth (n = 8) (control group, group B) were selected based on information in the Swedish AI-data
base. The experimental group consisted of 2 subgroups of heifers (groups A1 and A2) inseminated with 2 different bulls with
3.5% and 9% higher stillbirth rates than the average, and the control group consisted of heifers pregnant with 5 different
bulls with 0%–6% lower stillbirth rates than the average. The bull used for group A1 had also calving difficulties due to
large calves as compared to the bull in group A2 showing no calving difficulties. The heifers were supervised from 6–7 months
of pregnancy up to birth, and the pregnancies and parturitions were compared between groups regarding hormonal levels, haematology,
placental characteristics and calf viability. In group A1, 1 stillborn, 1 weak and 4 normal calves were recorded. In group
A2, 2 stillborn and 4 normal calves were registered. All animals in the control group gave birth to a normal living calf without
any assistance. The weak calf showed deviating profiles of body temperature, saturated oxygen and heart rates, compared with
the normal living calves. No differences of the placentome thickness, measured in vivo by ultrasonography were seen between the groups. The number of leukocytes and differential cell counts in groups A1 and A2
followed the profiles found in the control group. In group A1, a slight decrease of oestrone sulphate (E1SO4) levels was found
in the animal delivering a stillborn calf from the first 24-h blood sampling at 6 weeks to the second at 3 weeks prior to
delivery, while the levels of E1SO4 at both periods in the animal delivering a weak calf followed the profile in animals delivering
a normal living calf. During late pregnancy and at the time of parturition, the levels of E1SO4 and PAGs in animals delivering
a stillborn or weak calf (from group A1) followed the normal profiles found in animals delivering a normal living calf. In
group A2, low levels of E1SO4 and pregnancy associated glycoproteins (PAGs) over 24 h at both 3 and 6 weeks prior to parturition
(<1.5 nmol/L) were recorded in animals delivering a stillborn calf. During late pregnancy and parturition, the levels of E1SO4
and PAGs were slightly lower during 30–50 days prior to delivery and increased with a lower magnitude at the time of parturition.
In conclusion, our results indicate that the aetiology behind stillbirth varies depending on the AI-bulls used and is associated
with dystocia or low viability of the calves. Deviating profiles of oestrone sulphate (E1SO4) and pregnancy associated glycoproteins
(PAGs) in animals delivering a stillborn calf not caused by dystocia were observed, suggesting placental dysfunction as a
possible factor. The finding suggests that the analyses of E1SO4 and PAGs could be used for monitoring foetal well-being in
animals with a high risk of stillbirth at term. 相似文献
56.
T Yvanka de Soysa Allison Ulrich Timo Friedrich Danielle Pite Shannon L Compton Deborah Ok Rebecca L Bernardos Gerald B Downes Shizuka Hsieh Rachael Stein M Caterina Lagdameo Katherine Halvorsen Lydia-Rose Kesich Michael JF Barresi 《BMC biology》2012,10(1):1-25
Background
During nerve growth, cytoplasmic vesicles add new membrane preferentially to the growth cone located at the distal tip of extending axons. Growth cone membrane is also retrieved locally, and asymmetric retrieval facilitates membrane remodeling during growth cone repulsion by a chemorepellent gradient. Moreover, growth inhibitory factors can stimulate bulk membrane retrieval and induce growth cone collapse. Despite these functional insights, the processes mediating local membrane remodeling during axon extension remain poorly defined.Results
To investigate the spatial and temporal dynamics of membrane retrieval in actively extending growth cones, we have used a transient labeling and optical recording method that can resolve single vesicle events. Live-cell confocal imaging revealed rapid membrane retrieval by distinct endocytic modes based on spatial distribution in Xenopus spinal neuron growth cones. These modes include endocytic "hot-spots" triggered at the base of filopodia, at the lateral margins of lamellipodia, and along dorsal ridges of the growth cone. Additionally, waves of endocytosis were induced when individual filopodia detached from the substrate and fused with the growth cone dorsal surface or with other filopodia. Vesicle formation at sites of membrane remodeling by self-contact required F-actin polymerization. Moreover, bulk membrane retrieval by macroendocytosis correlated positively with the substrate-dependent rate of axon extension and required the function of Rho-family GTPases.Conclusions
This study provides insight into the dynamic membrane remodeling processes essential for nerve growth by identifying several distinct modes of rapid membrane retrieval in the growth cone during axon extension. We found that endocytic membrane retrieval is intensified at specific subdomains and may drive the dynamic membrane ruffling and re-absorption of filopodia and lamellipodia in actively extending growth cones. The findings offer a platform for determining the molecular mechanisms of distinct endocytic processes that may remodel the surface distribution of receptors, ion channels and other membrane-associated proteins locally to drive growth cone extension and chemotactic guidance. 相似文献57.
58.
Two polarized patterns (Th1 and Th2) of cytokines regulate inflammatory responses. Each cytokine pattern inhibits production of the opposing pattern. Lymphocytes from inflamed intestine due to Crohn's disease secrete a Th1 pattern of cytokines. Crohn's disease is most prevalent in highly industrialized countries with temperate climates. It occurs rarely in tropical third world countries with poor sanitation. We propose that exposure to an environmental agent predisposes individuals to Crohn's disease. Parasitic worms (helminths) are common in tropical climates and in populations subject to crowding and poor sanitation. Children are most subject to helminthic colonization. Many helminths live within or migrate through the human gut where they interact with the mucosal immune system. The host mounts a mucosal response that includes Th2 cytokine production limiting helminthic colonization. Helminths and their eggs probably are the most potent stimulators of mucosal Th2 responses. The Th2 response provoked by parasitic worms can modulate immune reactions to unrelated parasitic, bacterial, and viral infections. Many people in developed countries now live in increasingly hygienic environments, avoiding exposure to helminths. Perhaps failure to acquire these parasites and experience mucosal Th2 conditioning predisposes to Crohn's disease, which is an overly active Th1 inflammation. 相似文献
59.
S Larroudé N Massei P Reyes‐Marchant C Delattre JF Humbert 《Global Change Biology》2013,19(5):1620-1631
The impact of climate change and of other anthropogenic pressures on the structure and composition of phytoplankton communities of large European rivers remains poorly documented. Here we report the findings of a study of the changes in the phytoplankton community of the middle segment of the river Loire over the past 24 years. An attempt is made to distinguish between the impact of changes acting at the local scale and that of those acting more globally. A dramatic reduction in phytoplankton abundance was observed, particularly in the mid ‐1990s; this was concomitant with an increase in the relative proportion of cyanobacteria. At the same time, the phytoplankton community displayed increasing richness and diversity, and little change in its size structure. All these changes seem to be related to local changes, in particular to the reduction in phosphorus concentrations, as well as to changes in climate, throughout modifications in the river discharge and water temperature. Interestingly, herbicide contamination also appeared to be of particular importance in explaining the unexpected increase in the proportion of cyanobacteria in the phytoplankton community after the 1990s. These findings suggest that combinations of numerous anthropogenic pressures acting at different spatial and temporal scales have led to a mix of predictable and unpredictable changes occurring in the phytoplankton community of the river Loire, with probable consequences for the trophic networks in this river. 相似文献
60.
Victoria?PetriEmail author G?Thomas?Hayman Marek?Tutaj Jennifer?R?Smith Stanley?JF?Laulederkind Shur-Jen?Wang Rajni?Nigam Jeff?De Pons Mary?Shimoyama Melinda?R?Dwinell Elizabeth?A?Worthey Howard?J?Jacob 《Human genomics》2014,8(1):17