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71.
Limnology - External nutrient loading has a major influence on the abundance, composition and diversity of zooplankton communities. To clarify how the reduction of nutrient loading during lake... 相似文献
72.
73.
In this study, the interaction between cytidine and human serum albumin (HSA) was investigated for the first time by fluorescence spectroscopy in combination with UV absorption spectrum and molecular modeling under simulative physiological conditions. Experimental results indicated that cytidine had a strong ability to quench the intrinsic fluorescence of human serum albumin. The binding constants (K) at different temperatures, thermodynamic parameter enthalpy changes (DeltaH) and entropy changes (DeltaS) of HSA-cytidine had been calculated according to the relevant fluorescence data, which indicated that the hydrophobic and electrostatic interactions played a major role, which was in agreement with the results of molecular modeling study. In addition, the effects of other ions on the binding constants were also studied. Furthermore, synchronous fluorescence technology was successfully applied to the determination of human serum albumin added into the cytidine solution. 相似文献
74.
Despite advances in cryobiology, the reliable cryopreservation of complex tissues has not yet been achieved. This study evaluates the viability of cryopreserved composite flaps and demonstrates the feasibility of their transplantation. Epigastric flaps were harvested from male Lewis rats. 1.5 M dimethyl sulfoxide (Me2SO) was used as the initial cryoprotectant agent (CPA). Samples were frozen at controlled rate to −140 °C and transferred to liquid nitrogen for at least two weeks. Hematoxylin and eosin (H/E) staining, MTT tetrazolium salt assay, and factor VIII immunostaining were used to evaluate the overall histology, epithelial viability, and vascular endothelial integrity, respectively, of cryopreserved flaps. For the in vivo phase, flaps were isotransplanted to 35 recipient animals, divided into three groups: fresh (n = 10), perfused (n = 8), and cryopreserved (n = 17). Blood vessel patency was assessed via Doppler at 1, 7, and 60 days post-transplantation. For in vitro studies, cryopreserved samples (10/10) retained normal cell architecture and vascular endothelial integrity upon H/E and factor VIII staining. The viability index of cryopreserved composite flap skin (n = 10) was 11.17 ± 2.01, which was not significantly different from fresh controls (n = 10, 12.15 ± 1.32). All transplanted flaps in the fresh and perfusion groups survived with healthy color and hair growth at 60 days after operation. Survival in the cryopreserved group ranged from 2 to 60 days, with a mean of 12 days. These results demonstrate that the long term survival of cryopreserved composite tissue transplants is possible. Further studies are needed to refine protocols for the reliable cryopreservation of composite parts. 相似文献
75.
Ichikawa H No H Takei S Takashimizu I Yue F Cui L Ogiwara N Johkura K Nishimoto Y Sasaki K 《Cryobiology》2007,54(3):290-293
Cryopreservation of embryonic stem (ES) cells is essential to establish them as a resource for regenerative therapy. We evaluated survival adhesion rate, cell structure, gene expression, and multipotency of frozen and thawed embryoid bodies (EBs) derived from mouse ES cells. EBs were cryopreserved using the BICELL and the Program Freezer. After one week the EBs were thawed and cultured. EBs prepared in the Program Freezer had the highest survival adhesion (Program Freezer; 55-69%, BICELL; 30-38%). Though many cells in the thawed EBs were damaged, some were not, especially those prepared in the Program Freezer. RT-PCR analysis showed that genes characteristic of the three embryonic germ layers were expressed in thawed EBs cultured for one week. EBs transplanted into mice formed teratomas consisting of cells derived from the three germ layers. In conclusion, EBs frozen in the Program Freezer had higher survival adhesion rates compared to the BICELL and formed differentiated cells characteristic of the three embryonic germ layers. 相似文献
76.
Cereal beta-glucans can form aggregates in aqueous solution. The presence of aggregates in cereal beta-glucan solutions led to inaccurate determination of molecular weights and it was believed that intermolecular hydrogen bonding caused the aggregation. To eliminate aggregates, a carbanilation method for molecular weight determination of cereal beta-glucans was developed. Wheat beta-glucan samples were selected for investigation. The carbanilation method can prevent intermolecular hydrogen bonding by blocking hydroxyl groups with phenyl carbamate groups. The carbanilates of cereal beta-glucans were prepared by the reaction of cereal beta-glucans with phenylisocyanate catalyzed by DMSO and pyridine. To avoid degradation during the carbanilation reaction, relatively mild conditions were used, which led to incomplete substitution (DS: approximately 2). However, after the carbanilation reaction, the carbanilates dissolved completely in 1,4-dioxane solution without any detectable aggregates, which allowed accurate molecular weight determination. The degree of substitution (DS) of carbanilates was determined by both a nitrogen content method and an FT-IR method. The FT-IR method proved to be the more effective for DS estimation. Using this method, the converted molecular weights of cereal beta-glucans were in good agreement with the results measured in 0.5M NaOH solution, which previously was shown to be a good solvent for cereal beta-glucans. After the carbanilation reaction, conformational changes of carbanilates were studied by static and dynamic light scattering techniques. The fractal dimension (d(f)=2.27) and the structure sensitive parameters (rho >2) suggested a porous globular structure for partially carbanilated beta-glucans. 相似文献
77.
Phosphohistidine phosphatase 1 (PHPT1) is the first protein histidine phosphatase identified in vertebrates. The NMR assignments
of human PHPT1 are essential for solution structure determination and NMR study of the protein interactions of PHPT1 with
its potential substrates. 相似文献
78.
Li Nan Shi Hangyu Hou Pengfei Gao Lu Shi Yongqiang Mi Weiyang Zhang Gang Wang Ning Dai Wei Wei Lin Jin Tianbo Shi Yongzhi Guo Shiwen 《Functional & integrative genomics》2022,22(1):27-33
Functional & Integrative Genomics - This study ascertained to explore the potential contribution of ARRDC3 polymorphisms in the risk and prognosis of glioma. One thousand sixty-one patients and... 相似文献
79.
80.
Xiaojing Zhou Wen Wang Fang Cui Chunli Shi Yifei Ma Yongzhuo Yu Wei Zhao Jiaqing Zhao 《International journal for parasitology》2019,49(13-14):1029-1037
Cystic echinococcosis is a chronic and complex zoonotic disease. The mechanisms underlying the parasite’s establishment, growth and persistence are not completely understood, and are thought be modulated by a crosstalk through extracellular vesicles. Here, EVs were isolated from the hydatid cyst fluid of patients with cystic echinococcosis and protoscolex culture supernatant. Proteomic analysis of these EVs revealed several parasite- and human-derived proteins. Very few studies have performed proteomic analysis of EVs isolated from HCF and PCS. Our proteomic analysis of the EVs derived from HCF and PCS facilitated identification of 1175 proteins, wherein 1026 and 38 proteins were exclusively identified in the EVs derived from HCF (HCF-EVs) and PCS (PCS-EVs), respectively, and 111 proteins were shared in both. The results of co-culture of PCS-EVs with murine peripheral blood mononuclear cells showed that PCS-EVs significantly regulated T lymphocyte functions in a dose-dependent manner. Collectively, our results provide valuable information on parasite survival strategies and new insights into the role of these EVs in the establishment and persistence of hydatid cysts. 相似文献