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1.
Pravindra Kumar Javed A. Khan Savita Yadav Tej P. Singh 《Acta Crystallographica. Section D, Structural Biology》2002,58(2):225-232
Lactoferrin is an iron‐binding protein. In the iron‐bound state, the two domains of each lobe are invariably closed over an Fe3+ ion. On the other hand, the structures of iron‐free forms of lactoferrins from various species show different domain orientations. In order to determine the effects of external conditions such as pH, temperature and the presence of other additive agents on the crystal packing and consequently the influence of crystal packing forces on the final conformations of the two lobes of apolactoferrin, the structure of equine apolactoferrin has been determined at 303 K. The equine apolactoferrin was crystallized at 303 K using a microdialysis setup in which the concentration of protein was kept at 70 mg ml−1 in 0.025 M Tris–HCl pH 8.0 with a reservoir containing 19% ethanol in the same buffer. The structure has been determined by molecular replacement using equine diferric lactoferrin as a model and was refined to an R factor of 0.23. The value of the overall B factor in the present structure is 81.3 Å2. The overall structure of the protein is similar to its earlier structure based on crystals grown at 277 K as well as that of diferric equine lactoferrin. The N and C lobes have been found to be slightly differently oriented (4.9 and 7.1°, respectively) compared with the structures of equine diferric lactoferrin and apolactoferrin analyzed at 277 K, but the domain orientations in the two structures are identical as they remain closed over the empty iron‐binding cleft. Overall, the structures of equine diferric lactoferrin, equine apolactoferrin at 277 K and the present structure of equine apolactoferrin at 303 K display identical domain orientations, suggesting that variation in the temperature of crystal growth, data collection and the processes of iron binding and iron release do not influence the arrangements of domains in equine lactoferrin. 相似文献
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Lan GC Chang ZL Luo MJ Jiang YL Han D Wu YG Han ZB Ma SF Tan JH 《Molecular reproduction and development》2006,73(7):834-840
Dairy goats are ideal for the transgenic production of therapeutic recombinant proteins. The use of recombinant somatic cell lines for nuclear transfer (NT) allows the introduction of genes by transfection, increases the efficiency of transgenic animal production to 100%, and overcomes the problem of founder mosaicism. Although viable animals have been cloned via NT from somatic cells of 11 species, the efficiency has been extremely low. Both blastomere and somatic cell NT increased fetal loss and perinatal morbidity/mortality in cattle and sheep, but fetal loss and perinatal mortality appear to be relatively low in goats. In this study, we produced cloned goats by NT from cumulus cells and long-term cultured fetal fibroblast cells (FFCs) to abattoir-derived oocytes. NT embryos were constructed from electrofusion of cumulus cells (CCs), FFCs, or skin fibroblast cells (SFCs) with cytoplasts prepared from abattoir-derived ovaries. The NT embryos were activated with an optimized activating protocol (1 min exposure to 2.5 microM ionomycin followed by 2 hr incubation in 2mM 6-DMAP). Two viable cloned kids from CCs and one from long-term cultured FFCs (at passage 20-25) were born. Microsatellite analysis of 10 markers confirmed that all cloned offspring were derived from corresponding donor cells. To our knowledge, the production of cloned goat offspring using abattoir-derived oocytes receiving nuclei from CCs and long-term cultured FFCs has not been reported. The production of viable cloned animals after activation with reduced intensity of ionomycin and 6-DMAP treatment has also not been reported. Loss of cloned embryos was obvious after 45 and 90 days of pregnancy, and a lack of cotyledons, heart defects, and improperly closed abdominal wall were observed in the aborted fetuses and one cloned kid. The fusibility and in vitro developmental potential of embryos reconstructed from FFCs at passage 20-25 were significantly lower than those of embryos reconstructed from FFCs at passage 3-5, and the cloning efficiency of the long-term cultured cells was low (0.5%). 相似文献
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Stavros Giaglis Maria Stoikou Franco Grimolizzi Bibin Y. Subramanian Shane V. van Breda Irene Hoesli 《Cell Adhesion & Migration》2016,10(1-2):208-225
ABSTRACTAlmost 2 decades have passed since the discovery that pregnancy is associated with a basal inflammatory state involving neutrophil activation, and that this is more overt in cases with preeclampsia, than in instances with sepsis. This pivotal observation paved the way for our report, made almost a decade ago, describing the first involvement of neutrophil extracellular traps (NETs) in a non-infectious human pathology, namely preeclampsia, where an abundance of these structures were detected directly in the placental intervillous space.Despite these remarkable findings, there remains a paucity of interest among reproductive biologists in further exploring the role or involvement of neutrophils in pregnancy and related pathologies. In this review we attempt to redress this deficit by highlighting novel recent findings including the discovery of a novel neutrophil subset in the decidua, the interaction of placental protein 13 (PP13) and neutrophils in modulating spiral artery modification, as well as the use of animal model systems to elucidate neutrophil function in implantation, gestation and parturition. These model systems have been particularly useful in identifying key components implicated in recurrent fetal loss, preeclampsia or new signaling molecules such as sphingolipids. Finally, the recent discovery that anti-phospolipid antibodies can trigger NETosis, supports our hypothesis that these structures may contribute to placental dysfunction in pertinent cases with recurrent fetal loss. 相似文献
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Yongjun Du Ping Li Zhiqun Chen Yanru Lin Yahong Wang Yuanxia Qin 《Entomologia Experimentalis et Applicata》2013,146(3):357-363
The sex pheromone of Phyllonorycter ringoniella (Matsumura) (Lepidoptera: Gracillariidae) has been identified to be a blend of (Z)‐10‐tetradecenyl acetate (Z10‐14:OAc) and E4,Z10‐tetradecadienyl acetate (E4,Z10‐14:OAc) in Japan, Korea, and China. However, the commercial product based on previous results is not attractive enough to be used for monitoring and controlling apple leafminer populations in the field. We re‐investigated the attractiveness of the two pheromone components, singly and in blends, in apple orchards in Shangdong and Shaanxi, the main apple‐growing provinces in China. Our results revealed that Z10‐14:OAc alone was not attractive to P. ringoniella male moths in the field, but E4,Z10‐14:OAc alone not only was strongly attractive but caught more males than any of the blends of Z10‐14:OAc and E4,Z10‐14:OAc tested. The most attractive blend ratios differed slightly for the two locations. No clear dose–response relationship was obtained for the 2:8 blend of Z10‐14:OAc and E4,Z10‐14:OAc. However, the dose–response field study of E4,Z10‐14:OAc alone showed that 1 mg per lure achieved the highest moth catch. These findings differ from the previous report of the best pheromone blend in China. Our data showed that E4,Z10‐14:OAc is the major component of the pheromone of P. ringoniella. 相似文献
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Mauro Simonato Andrea Battisti Daniel Zovi Raul F. Medina 《Entomologia Experimentalis et Applicata》2012,145(2):124-133
Several studies underline the importance of ecological barriers and differential selection in driving sympatric speciation. Host‐associated differentiation (HAD) has been proposed as one of the mechanisms leading to sympatric speciation. However, it is still unclear how common HAD is or which are the factors that could promote it. In particular, not much is known about HAD in predators and parasitoids of herbivorous insects. One of the characteristics postulated to pre‐dispose insects to HAD is parthenogenesis as it may favour adaptive responses to particular environments, amplifying selected gene complexes. In this study, we used amplified fragment length polymorphism (AFLP) markers to determine whether HAD is present in two parthenogenetic egg parasitoids attacking the same herbivore species – the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermüller) (Lepidoptera: Notodontidae) – on two host Pinus species. A total of 100 loci for 59 individuals sampled in four populations of Baryscapus servadeii (Domenichini) (Hymenoptera: Eulophidae), a specialist parasitoid, and 106 loci for 117 individuals sampled in six populations of Ooencyrtus pityocampae Mercet (Hymenoptera: Encyrtidae), a generalist parasitoid, were analysed. Levels of genetic differentiation were also assessed with an outlier analysis, checking for alleles associated to host plants. No evidence of HAD was detected in any of the two parasitoid species. We hypothesize that both the lack of strict parthenogenetic reproduction and the ectophagous nature of the insect host could explain the absence of HAD. The genetic variation observed in the generalist parasitoid responded to a pattern of local adaptation, whereas no relationship with either host or geography was found in the specialist parasitoid. 相似文献
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The effects of exposure to different concentrations of phenoxyherbicides and their metabolites were studied in human erythrocytes, with particular attention to catalase (CAT-EC. 1.11.1. 6- hydrogen peroxide: hydrogen peroxide oxidoreductase). 4-chloro-2-methylphenoxyacetic acid (MCPA), 2,4-dimethylphenol (2, 4-DMP) and 2,4-dichlorophenoxyacetic acid (2,4-D) did not affect CAT activity, but 2,4-dichlorophenol (2,4-DCP) and 2,4,5-trichlorophenol (2,4,5-TCP) decrease its activity, the latter being the more inhibitory. 相似文献
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Simultaneous nitrification and denitrification (SND) via the nitrite pathway and anaerobic-anoxic-enhanced biological phosphorus removal (EBPR) are two processes that can significantly reduce the energy and COD demand for nitrogen and phosphorus removal. The combination of these two processes has the potential of achieving simultaneous nitrogen and phosphorus removal with a minimal requirement for COD. A lab-scale sequencing batch reactor (SBR) was operated in alternating anaerobic-aerobic mode with a low dissolved oxygen (DO) concentration (0.5 mg/L) during the aerobic period, and was demonstrated to accomplish nitrification, denitrification, and phosphorus removal. Under anaerobic conditions, COD was taken up and converted to polyhydroxyalkanoates (PHAs), accompanied by phosphorus release. In the subsequent aerobic stage, PHA was oxidized and phosphorus was taken up to <0.5 mg/L by the end of the cycle. Ammonia was also oxidized during the aerobic period, but without accumulation of nitrite or nitrate in the system, indicating the occurrence of simultaneous nitrification and denitrification. However, off-gas analysis showed that the final denitrification product was mainly nitrous oxide (N(2)O), not N(2). Further experimental results demonstrated that nitrogen removal was via nitrite, not nitrate. These experiments also showed that denitrifying glycogen-accumulating organisms (DGAOs), rather than denitrifying polyphosphate-accumulating organisms (DPAOs), were responsible for the denitrification activity. 相似文献
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This study aimed to evaluate the effect of previous exposure to the essential oil of lemongrass [Cymbopogon citratus (DC) Stapf (Poaceae)] on the chemotactic behavior of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) larvae and adults. All insect responses were evaluated using a Y‐tube (dual choice) olfactometer. Experience with the essential oil for 48 h after hatching did not change the chemotactic behavior of larvae; however, when they were exposed to lemongrass for 10–12 consecutive days, they did not present a preference for either treatment. Adults originating from larvae exposed to the essential oil odor until the formation of pupae responded more to this treatment in comparison to acetone. Similar results were obtained with insects exposed for only 24 h (at the end of the last instar) to the same treatment. Similar to inexperienced individuals, adults exposed for 48 h after emergence to acetone were significantly more responsive to this compound than to the essential oil. However, insects exposed to lemongrass odor during the same period displayed no preference for either treatment. This study demonstrated that both larvae and adults of G. molesta are capable of non‐associative learning and the memory acquired in the larval stage is maintained for at least 48 h after emergence. 相似文献
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Feng Wang Lijun Wu Baris Key Xiao‐Qing Yang Clare P. Grey Yimei Zhu Jason Graetz 《Liver Transplantation》2013,3(10):1324-1331
Silicon‐based anodes are an appealing alternative to graphite for lithium‐ion batteries because of their extremely high capacity. However, poor cycling stability and slow kinetics continue to limit the widespread use of silicon in commercial batteries. Performance improvement has been often demonstrated in nanostructured silicon electrodes, but the reaction mechanisms involved in the electrochemical lithiation of nanoscale silicon are not well understood. Here, in‐situ synchrotron X‐ray diffraction is used to monitor the subtle structural changes occurring in Si nanoparticles in a Si‐C composite electrode during lithiation. Local analysis by electron energy‐loss spectroscopy and transmission electron microscopy is performed to interrogate the nanoscale morphological changes and phase evolution of Si particles at different depths of discharge. It is shown that upon lithiation, Si nanoparticles behave quite differently than their micrometer‐sized counterparts. Although both undergo an electrochemical amorphization, the micrometer‐sized silicon exhibits a linear transformation during lithiation, while a two‐step process occurs in the nanoscale Si. In the first half of the discharge, lithium reacts with surfaces, grain boundaries and planar defects. As the reaction proceeds and the cell voltage drops, lithium consumes the crystalline core transforming it into amorphous LixSi with a primary particle size of just a few nanometers. Unlike the bulk silicon electrode, no Li15Si4 or other crystalline LixSi phases were formed in nanoscale Si at the fully‐lithiated state. 相似文献
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用正常人胎肺细胞体外培养,从其培养液中分离纤溶酶原活化物（ＰＡ）,通过ＣＭ－ＳｅｐｈａｄｅｘＣ－５０层析,硫酸铵沉淀和Ｆｉｂｒｉｎ－Ｓｅｐｈａｒｏｓｅ,Ｌｙｓｉｎｅ－Ｓｅｐｈａｒｏｓｅ亲和层析及ＳｅｐｈａｄｅｘＧ－５０凝胶过滤等步骤,从１０．５ｌ条件培养液中分离纯化得到两种类型的纤溶酶原活化物,ｔ－ＰＡ９０μｇ,ｕ－ＰＡ８００μｇ．在还原条件下ＳＤＳ－ＰＡＧＥ均显示单带,分子量ｔ－ＰＡ为７２ｋＤ,ｕ－ＰＡ为５４ｋＤ,纤溶比活分别为１５６０００ＩＵ／ｍｇ蛋白和１０６０００ＩＵ／ｍｇ蛋白． 相似文献
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The high-pressure freezing (HPF) technique was applied to the cryo-immobilization of alginate gels and the quality of the freezing analyzed on a TEM by comparison of the segregation pattern of samples of decreasing thickness. Dynamic simulations of heat transfer within an idealized slab of pure water surrounded by two walls of aluminium were performed to illustrate the effect of the heat-transfer coefficient by convection on the cooling rate of the sample. Heat-transfer coefficients in liquid nitrogen and liquid propane at ambient pressure were measured using a carefully characterized thermocouple and the values incorporated as parameters in heat-transfer simulations to compare the efficiency of the plunge-freezing technique with the high-pressure freezing technique. Values of the heat-transfer coefficient in liquid nitrogen and liquid propane, calculated between 273 K and 173 K were 670 and 18420 W/m(2)/K, respectively. Based on TEM observations and the results of heat-transfer simulations, the HPF technique was adapted to the cryo-fixation of 50-microm-thick alginate gels. The occurrence of artifacts was rejected because no differences were observed in the pattern of cryo-fixed and freeze-substituted samples of various thickness, with and without ethanol as cryo-protectant. A sample thickness of 50 microm was found to ensure an adequate preservation of structures as small as a few nanometers, as verified by TEM and SEM observations. Finally, DSC measurements on alginate solutions and alginate beads revealed that under the experimental conditions (0-3%), alginate cannot be considered to be an efficient cryo-protectant. 相似文献
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To discriminate between stable and dynamic protein-protein interactions, we propose a strategy in which cells with and without tagged bait are differentially labeled with stable isotope and combined prior to complex purification. Mass-spectrometric analysis of the purified complexes identifies stable and dynamic components as those derived exclusively from the tagged cells and those from both cells, respectively. We successfully applied this strategy to analyze two yeast protein complexes, eIF2B-eIF2 and cyclin-Cdc28. 相似文献
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The ontogeny of gamma-glutamyl transferase (GGTase; E.C.2.3.2.2) and tyrosine aminotransferase (TAT; E.C.2.6.1.5) activities in 14 to 36 weeks gestational and neonatal hepatocytes during development of human fetal liver was studied. Subsequently, 20-24 weeks gestational hepatocytes were cultured in media supplemented with epidermal growth factor (EGF) and insulin with or without glucagon and dexamethasone to investigate the proliferation and differentiation of fetal hepatocyte in vitro using GGTase and TAT as biochemical markers. During the development of the liver, the activity of GGTase increased continuously from the first trimester through the third trimester and decreased (p < 0.001) in neonates. A low basal level of TAT activity was seen only during the third trimester, which then increased significantly (p < 0.001) in neonates. Fetal hepatocytes, in the presence of EGF and insulin, undergo proliferation from the fourth to 10th day with an increase in cell number (p < 0.001) and concomitant increase (p < 0.001) in GGTase activity. As the cells attain confluence, enzyme activity decreased significantly (p < 0.001) from the 10th to 16th day. Maximal TAT activity (p < 0.001) was observed at 48 h of culture, which decreased, but not significantly, during cell proliferation and the enzyme activity was regained as the cultures attained confluence. Furthermore, TAT activity was induced synergistically (p<0.001) in the presence of glucagon and dexamethasone, while GGTase was inhibited (p<0.001). These results indicate that GGTase increases with proliferation, whereas TAT, once it has been expressed, is not suppressed during cell proliferation. In conclusion, human fetal hepatocytes undergo enzymic differentiation by 48 h of culture, and proliferate with an increase in GGTase in the presence of growth factors with maintenance of differentiated status up to the studied 16 days of culture. 相似文献
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Junichi Tsuchiya;Yoshinori Maki;Madoka Ayano;Taiki Kikuchi;Yosuke Watanabe;Kiyoshi Ohtake;Rumi Fujita;Masaru Hayashi;Junji Yamamoto;Ying Wang;Atsushi Anzai;Tomohiro Kubo;Soichi Sano; 《Advanced Biosystems》2024,8(7):2300512
The phenomenon of sex chromosome loss from hematopoietic cells is an emerging indicator of biological aging. While many methods to detect this loss have been developed, enhancing the field, these existing methods often suffer from being labor-intensive, expensive, and not sufficiently sensitive. To bridge this gap, a novel and more efficient technique is developed, named the SinChro assay. This method employs multiplexed single-cell droplet PCR, designed to detect cells with sex chromosome loss at single-cell resolution. Through the SinChro assay, the age-dependent increase in Y chromosome loss in male blood is successfully mapped. The age-dependent loss of the X chromosome in female blood is also identified, a finding that has been challenging with existing methods. The advent of the SinChro assay marks a significant breakthrough in the study of age-related sex mosaicism. Its utility extends beyond blood analysis, applicable to a variety of tissues, and it holds the potential to deepen the understanding of biological aging and related diseases. 相似文献
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Laura Lucarini Alessandro Pini Elisabetta Gerace Roberto Pellicciari Emanuela Masini Flavio Moroni 《Journal of cellular and molecular medicine》2014,18(3):468-479
Activation of poly(ADP‐ribose) polymerases (PARPs) is considered a key event in the molecular and cellular processes leading from acute asthma attacks to bronchial hyper‐reactivity, leucocyte recruitment, chronic inflammation, airway remodelling and lung damage. The present investigation has been carried out to investigate the action of hydroxyl‐dimethylaminomethyl‐thieno[2,3‐c]isoquinolin‐5(4H)‐one (HYDAMTIQ), a new potent PARP inhibitor, in the process leading from asthma‐like events to airway damage. Ovalbumin‐sensitized guinea pigs exposed two times to allergen inhalation were treated for 8 days with vehicle or HYDAMTIQ. Asthma‐like signs, bronchial hyper‐reactivity to methacholine, cytokine production, histamine release from mast cells, airway remodelling, collagen deposition and lung damage were evaluated. Repeated HYDAMTIQ administration (1‐10 mg/kg/day i.p.) reduced lung PARP activity, delayed the appearance and reduced the severity of allergen‐induced cough and dyspnoea and dampened the increased bronchial responses to methacholine. HYDAMTIQ‐treated animals presented reduced bronchial or alveolar abnormalities, lower number of eosinophils and other leucocytes in the lung and decreased smooth muscle or goblet cell hyperplasia. The treatment also reduced lung oxidative stress markers, such as malondialdehyde or 8‐hydroxy‐2′‐deoxyguanosine and the lung content of pro‐inflammatory cytokines (TNF‐α, interleukin (IL)‐1β, IL‐5, IL‐6 and IL‐18). Finally, mast cells isolated from the peritoneal or pleural cavities of sensitized, HYDAMTIQ‐treated animals had a reduced ability to release histamine when exposed to ovalbumin in vitro. Our findings support the proposal that PARP inhibitors could have a therapeutic potential to reduce chronic lung inflammation, airway damage and remodelling in severe unresponsive asthmatic patients. 相似文献
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