During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century...During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century. Here we report on new details concerning the conjugation of P. caudatum through the staining of conjugating ceils with protargol, carbol fuchsin solution, Hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-a tubulin. 1) The crescent nucleus is a characteristic of the meiotic prophase of P. caudatum, has an unstained area. We stained this area with protargol, which was separated from the chromatin area and was not detected by the other stainings. 2) In regards to the four meiotic products, it has long been considered that only one product enters the paroral cone region (PC) and survives after meiosis. However, our protargol and immunofluorescence labeling results indicated that PC entrance of the meiotic product happened before the completion of meiosis instead of after. 3) In our previous study, protargol staining indicated the presence of a swollen structure around the central part of the "U" and "V" shaped spindles connecting the two types of prospective pronuclei. However, immunofluorescence labeling with anti-a tubulin antibodies gave a different image from protargol. All these observations form the basis for further studies of their molecular mechanisms.展开更多
Objective To probe into whether an acupoint-like and meridian-like structure was existed in platyfish. Methods Adult platyfish was put in 30 μM 4-Di-2-ASP water solution for 3 h, then, in pipe water for 20min, afterw...Objective To probe into whether an acupoint-like and meridian-like structure was existed in platyfish. Methods Adult platyfish was put in 30 μM 4-Di-2-ASP water solution for 3 h, then, in pipe water for 20min, afterward, the fish was anesthetized in 10% aether water solution, and the fluorescent labeling was observed under fluorescent microscope with B-3A combination filter. Results The labels observed under the microscope were in round bright dot, a majority of dots were distributed separately and a part of them was in cluster (2- 5 dots/cluster) on various parts of the body in regular arrangement. The labels on the head were circularly distributed around the eye and two arches were formed posterior to the eye and in the inferior 3/4 quadrant. These two arches joined one arch in the anterior superior 1/4 quadrant. On the fish trunk, it was observed that the labels were distributed from the back to the abdomen along the longitudinal axis of the trunk, forming 6 lines, located on No. 2, 4, 6, 7, 8 and 9 scale rows successively on the dorsal part of fish. Each line was composed of 7 to 22 label clusters and 1 -5 labels were counted in each cluster. The labels were arranged as 3-4 lines on the tail. Conclusion 1) Acupoint-like and meridian-like structure was existed in platyfish. 2)The skin sensory organs of animal were not distributed evenly all over the body. Instead, a number of sensory organs were put together in cluster and a number of them were in linear distribution regularly along the long axis of the trunk, which was similar to the distribution of traditional meridians and acupoints.展开更多
The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evalua...The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris 〉 P. helgolandicavar 〉 L galbana 〉 N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar 〉 N. closterium 〉 C. vulgaris 〉 L galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×10^6 cells mL^-1 for C. vulgaris and 1.5×10^6 cells mL^-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase 〉 exponential phase 〉 lag phase 〉 decline phase. Additionally, the filtering rates during the growth phases were: exponential phase 〉 lag phase 〉 stationary phase 〉 decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.展开更多
Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectr...Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS) for direct analysis of total lipid extracts.Mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode.Phospholipid molecular species identification was based on the characteristic product ions and neutral loss yielded by different phospholipids under ESI-MS/MS mode.The molecular species were confirmed by the carboxylate anions produced by phospholipids in negative mode;the regiospecificity of the two acyl chains was determined from the ratio of sn-1 to sn-2 carboxylate anion abundances.As a result,18 lipid molecular species were identified for the first time in this microalga,comprising seven phosphatidylcholines (PC),two phosphatidylethanolamines (PE),two phosphatidylinositols (PI),and seven phosphatidylglycerols (PG).Lipid standards of PC,PE,PI,and PG were added to the total lipids as internal standards for semiquantitative analysis,revealing concentrations of phospholipids in this species between 0.09 and 3.37 nmol/mg.This method can produce a full structural profile of intact phospholipid molecular species and can be used for study of the physiological and ecological functions of lipids by monitoring their individual changes over time.展开更多
In this study, biosilica of high purity was successfully prepared from marine diatom (Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal t...In this study, biosilica of high purity was successfully prepared from marine diatom (Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600℃. The SiO2 contents of N. closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO2 morphologies of both biosilica are typical amorphous silica. Besides, IV. closterium biosilica possessed micropores and fibers with a surface area of 59.81 m^2/g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91 m^2/g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.展开更多
Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in...Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia(July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling(MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds.展开更多
The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with ...The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with their nuclear-encoded small-subunit ribosomal RNA (SSU rDNA) and chloroplast-encoded rbcL gene sequences determined in this study. Interestingly, very high sequence divergences of SSU rDNA and rbcL gene were found among these isolates, and numerous nucleotide variation of rbcL gene caused relatively few variation of deduced amino acid sequence. Phylogenetic analyses based on SSU rDNA and rbcL gene, respectively, grouped the isolates into 6 clades. Phylogenetic tree of SSU rDNA placed all the Cylindrotheca isolates together, separating them into two lineages clearly. LineageⅠ was composed of the eleven C. closterium isolates obtained in this study together with another C. closterium isolate, but some clades were not well supported. LineageⅠwas contained two C. closterium isolates and one C. fusiformis isolate. Phylogenetic analysis of rbcL gene also separated the Cylindrotheca isolates into two well-defined lineages. The eleven C. closterium isolates formed a lineage and all clades were supported strongly. Statistical comparisons of SSU rDNA indicated that the average distance within lineageⅠwas significantly higher than that of other microalgae species (P 〈0.01). These results suggested the existence of cryptic species within C. closterium.展开更多
A press conference was held in Beijing on August 23,marking the launch of a public competitive campaign to obtain a name and logo for China’s Mars mission.The project and its progress were introduced at the conferenc...A press conference was held in Beijing on August 23,marking the launch of a public competitive campaign to obtain a name and logo for China’s Mars mission.The project and its progress were introduced at the conference and the external appearance of the Mars probe and the rover was revealed.China’s Mars mission will be implemented in two steps.The objective of the first step is to achieve orbiting,landing,and roving.Mars sampling will be the purpose of the second step。展开更多
OBJECTIVE: To study glomerular expression of C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha and beta (MIP-1alpha, MIP-1beta) and the effect of steroid and cyclophosp...OBJECTIVE: To study glomerular expression of C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha and beta (MIP-1alpha, MIP-1beta) and the effect of steroid and cyclophosphamide (CTX) intermittent intravenous pulse therapy on expression in patients with crescentic glomerulonephritis (CGN) to further investigate the underlying mechanism of the treatment. METHODS: Twelve patients with initial biopsy-proven CGN(2), 6 with lupus nephritis (lupus-CGN, LN-CGN) and 6 with vasculitis, (vasculitis-CGN, V-CGN) were enrolled in this study. They underwent an initial biopsy before steroid and CTX intermittent intravenous pulse therapy and were biopsied again one to three months later. Expression of MCP-1, MIP-1alpha, MIP-1beta, and CD68 in glomeruli with cellular and fibrocellular crescents were examined by immunohistochemical analysis in serial sections of renal biopsies. The effect of the pulse therapy on histopathological changes was also observed. RESULTS: Although steroid and CTX intermittent intravenous pulse therapy markedly reduced the degree of glomerular crescent formation both in LN-CGN and V-CGN, the effect of the therapy on glomerular chemokine expression was significantly different between LN-CGN and V-CGN. It was found that steroid and CTX intermittent intravenous pulse therapy reduced the expression of CD68, MCP-1, and MIP-1alpha, but had no effect on MIP-1beta in glomeruli with cellular crescents of patients with LN-CGN. In patients with V-CGN, the therapy also reduced the expression of CD68, but had no effect on MCP-1, MIP-1alpha, and MIP-1beta in glomeruli with cellular crescents. It was noted that the degree of glomerulosclerosis and tubular interstitial fibrosis increased more significantly at the second biopsy in V-CGN as compared to LN-CGN. CONCLUSIONS: The efficacy of steroid and CTX intermittent intravenous pulse therapy in CGN might be affected by reduction of glomerular chemokine expression. The different changes in glomerular expression of MCP-1 and MIP-1alpha in patients with LN-CGN and V-CGN after pulse therapy may correlate to different responses to treatment and prognosis.展开更多
Objective To study the significance and distribution of renal infiltrating cells, including monocytes (CD68+ cells), proliferative cell nuclear antigen positive cells (PCNA+ cells), CD4+ and CD8+ cells in diffuse cres...Objective To study the significance and distribution of renal infiltrating cells, including monocytes (CD68+ cells), proliferative cell nuclear antigen positive cells (PCNA+ cells), CD4+ and CD8+ cells in diffuse crescent glomerulonephritis (DCGN). Methods Fifty-six patients with DCGN were studied, including 10 cases of anti-glomerular basement membrane (GBM)-type Ⅰ DCGN, 26 immune complex-type Ⅱ DCGN, and 20 cases of pauci-immune-type Ⅲ DCGN. Glomerular and interstitial infiltrates of CD68+ and PCNA+ cells, and interstitial infiltrates of CD4+ and CD8+ cells were detected by using four-layer PAP methods. Results There was a significant increase of renal infiltrating CD68+, PCNA+, CD4+ and CD8+ cells in patients with DCGN compared with that in normal controls. In patients with type Ⅰ DCGN, there was a higher number of renal infiltrating CD68+ and PCNA+ cells than that in patients with type Ⅱ and Ⅲ DCGN. A glomerular infiltrates of CD68+ and PCNA+ cells correlated with the interstitial infiltrates of CD4+ cells in type Ⅰ or Ⅲ DCGN patients. In lupus DCGN patients, the numbers of renal infiltrating CD68+ and PCNA+ cells were similar to vasculitis or type Ⅲ DCGN patients.Conclusion These findings demonstrate that the renal infiltrates of CD68+ and PCNA+ cells play an important role in patients with DCGN, that the infiltrates of CD4+ cells correlate with the infiltrates of CD68+ and PCNA+ cells may be an active marker of DCGN, and that cell-mediated immunity may contribute to crescent formation in lupus DCGN patients.展开更多
Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and alb...Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and albedo between crescent sand ridges and tongue-shaped dunes,and between windward and leeward slopes of tongue-shaped dunes,result in their feathery appearance in aerial and satellite imagery.Measurements of the sand drift potential in the region show that the sand-moving wind for feathered sand ridges can be divided into three sectors;i.e.north-northeasterly,easterly and east-northeasterly sectors roughly corresponding to the southeast,northwest and southwest slip faces.Our findings suggests that the crescent sand ridges resulting from the connection of barchan dunes along the prevailing wind direction are longitudinal dune ridges rather than transverse ones.Tongue-shaped dunes and quasi-dune shapes have obvious distinctions and are new transverse dune types.According to McKee's dune shape classification,the feathered sand ridges are not a deformation dune type but a complex one.According to Wu's dune morphological and genetic classification,they are not dune ridges or compound dune ridges that form under the action of unidirectional winds or two winds intersecting at an acute angle,but are complex dune ridges that form under the action of three winds intersecting at an acute angle.展开更多
Objective: To assess the lower tear meniscus height(LTMH), central tear film thickness(CTFT), and central corneal epithelial thickness(CCET) after deep anterior lamellar keratoplasty(DALK). Methods: This was...Objective: To assess the lower tear meniscus height(LTMH), central tear film thickness(CTFT), and central corneal epithelial thickness(CCET) after deep anterior lamellar keratoplasty(DALK). Methods: This was a retrospective cross-sectional study of 20 patients who had DALK in one eye over a three-month period. LTMH, CTFT, and CCET of the operated eyes and the unoperated fellow eyes were measured using high-definition optical coherence tomography(HD-OCT). Correlations between three OCT assessments and age, time following surgery, graft size, bed size, and the number of residual sutures were analyzed. Results: Compared to patients with keratoconus, patients with other corneal conditions had significantly higher CCET in the fellow eye(P=0.024). For all patients, CCET in the operated eye was significantly negatively correlated with the number of residual sutures(R=-0.579, P=0.008), and was significantly positively correlated with time following surgery(R=0.636, P=0.003). In the fellow eye, a significant positive correlation was found between age and CCET(R=0.551, P=0.012), and a significant negative correlation between age and CTFT(R=-0.491, P=0.028). LTMH was found to be significantly correlated between operated and fellow eyes(R=0.554, P=0.011). There was no significant correlation between LTMH and age, bed/graft size, time following surgery, or residual sutures(all possible correlations, P0.05). Conclusions: Patients with keratoconus tend to have a thinner central corneal epithelium. Corneal epithelium keeps regenerating over time after DALK. DALK did not induce a significant change in tear volume compared with the fellow eye. Postoperative tear function might depend on an individual's general condition, rather than on age, gender, bed/graft size, time following surgery, or residual sutures.展开更多
The migration of a downsized crescent-shaped dune was investigated in a wind tunnel experiment.Quantified upwind influx and vertical oscillation of the sand bed were introduced to modulate the saturation level of the ...The migration of a downsized crescent-shaped dune was investigated in a wind tunnel experiment.Quantified upwind influx and vertical oscillation of the sand bed were introduced to modulate the saturation level of the sand flux above the dune surface to affect dune evolution.The evolution was recorded by top-view photography and then abstracted as the evolution of self-defined characteristic quantities using a digital image processing algorithm.The results showed that,in contrast to the case for spanwise quantities,the evolution of streamwise quantities corresponds to a linear increase in the modulation magnitude more positively and in a monotonic and convergent manner.In contrast with quantities on the windward face,the changes in quantities with respect to the horns were nonmonotonic with time and almost uncorrelated with the variation in modulation strength,which reveals the distinctiveness of leeside evolution.展开更多
文摘During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century. Here we report on new details concerning the conjugation of P. caudatum through the staining of conjugating ceils with protargol, carbol fuchsin solution, Hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-a tubulin. 1) The crescent nucleus is a characteristic of the meiotic prophase of P. caudatum, has an unstained area. We stained this area with protargol, which was separated from the chromatin area and was not detected by the other stainings. 2) In regards to the four meiotic products, it has long been considered that only one product enters the paroral cone region (PC) and survives after meiosis. However, our protargol and immunofluorescence labeling results indicated that PC entrance of the meiotic product happened before the completion of meiosis instead of after. 3) In our previous study, protargol staining indicated the presence of a swollen structure around the central part of the "U" and "V" shaped spindles connecting the two types of prospective pronuclei. However, immunofluorescence labeling with anti-a tubulin antibodies gave a different image from protargol. All these observations form the basis for further studies of their molecular mechanisms.
文摘Objective To probe into whether an acupoint-like and meridian-like structure was existed in platyfish. Methods Adult platyfish was put in 30 μM 4-Di-2-ASP water solution for 3 h, then, in pipe water for 20min, afterward, the fish was anesthetized in 10% aether water solution, and the fluorescent labeling was observed under fluorescent microscope with B-3A combination filter. Results The labels observed under the microscope were in round bright dot, a majority of dots were distributed separately and a part of them was in cluster (2- 5 dots/cluster) on various parts of the body in regular arrangement. The labels on the head were circularly distributed around the eye and two arches were formed posterior to the eye and in the inferior 3/4 quadrant. These two arches joined one arch in the anterior superior 1/4 quadrant. On the fish trunk, it was observed that the labels were distributed from the back to the abdomen along the longitudinal axis of the trunk, forming 6 lines, located on No. 2, 4, 6, 7, 8 and 9 scale rows successively on the dorsal part of fish. Each line was composed of 7 to 22 label clusters and 1 -5 labels were counted in each cluster. The labels were arranged as 3-4 lines on the tail. Conclusion 1) Acupoint-like and meridian-like structure was existed in platyfish. 2)The skin sensory organs of animal were not distributed evenly all over the body. Instead, a number of sensory organs were put together in cluster and a number of them were in linear distribution regularly along the long axis of the trunk, which was similar to the distribution of traditional meridians and acupoints.
基金Supported by Natural Science Foundation of China (No 30270258)Program for New Century Excellent Talents in University (NCET-05-0597)
文摘The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris 〉 P. helgolandicavar 〉 L galbana 〉 N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar 〉 N. closterium 〉 C. vulgaris 〉 L galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×10^6 cells mL^-1 for C. vulgaris and 1.5×10^6 cells mL^-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase 〉 exponential phase 〉 lag phase 〉 decline phase. Additionally, the filtering rates during the growth phases were: exponential phase 〉 lag phase 〉 stationary phase 〉 decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) (No. IRT0734)Zhejiang Provincial Natural Science Foundation (No. Y506131)+1 种基金National Key Technology Research and Development Program (No. 2007BAD43B09)K. C. Wong Magna Fund of Ningbo University
文摘Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS) for direct analysis of total lipid extracts.Mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode.Phospholipid molecular species identification was based on the characteristic product ions and neutral loss yielded by different phospholipids under ESI-MS/MS mode.The molecular species were confirmed by the carboxylate anions produced by phospholipids in negative mode;the regiospecificity of the two acyl chains was determined from the ratio of sn-1 to sn-2 carboxylate anion abundances.As a result,18 lipid molecular species were identified for the first time in this microalga,comprising seven phosphatidylcholines (PC),two phosphatidylethanolamines (PE),two phosphatidylinositols (PI),and seven phosphatidylglycerols (PG).Lipid standards of PC,PE,PI,and PG were added to the total lipids as internal standards for semiquantitative analysis,revealing concentrations of phospholipids in this species between 0.09 and 3.37 nmol/mg.This method can produce a full structural profile of intact phospholipid molecular species and can be used for study of the physiological and ecological functions of lipids by monitoring their individual changes over time.
基金Supported by the Public Science and Technology Research Funds Projects of Ocean,China(No.201305022)the PhD Start-up Fund of Natural Science Foundation of Guangdong Province,China(No.2014A030310326)
文摘In this study, biosilica of high purity was successfully prepared from marine diatom (Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600℃. The SiO2 contents of N. closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO2 morphologies of both biosilica are typical amorphous silica. Besides, IV. closterium biosilica possessed micropores and fibers with a surface area of 59.81 m^2/g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91 m^2/g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.
基金Supported by the National Key Technology R&D Program of China(No.2006BAD09A01)the Science and Technology Development Project in Shandong Province(No.2010GHY10505)the Science and Technology Development Project of Yantai(No.2011049)
文摘Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia(July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling(MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds.
基金This research was financially supported by an open project of The Key Laboratory of Mariculture of The Ministry of Education of China affiliated to 0cean umversity of China(200405)by the National Natural Science Foundation of China(30471318,40176028).
文摘The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with their nuclear-encoded small-subunit ribosomal RNA (SSU rDNA) and chloroplast-encoded rbcL gene sequences determined in this study. Interestingly, very high sequence divergences of SSU rDNA and rbcL gene were found among these isolates, and numerous nucleotide variation of rbcL gene caused relatively few variation of deduced amino acid sequence. Phylogenetic analyses based on SSU rDNA and rbcL gene, respectively, grouped the isolates into 6 clades. Phylogenetic tree of SSU rDNA placed all the Cylindrotheca isolates together, separating them into two lineages clearly. LineageⅠ was composed of the eleven C. closterium isolates obtained in this study together with another C. closterium isolate, but some clades were not well supported. LineageⅠwas contained two C. closterium isolates and one C. fusiformis isolate. Phylogenetic analysis of rbcL gene also separated the Cylindrotheca isolates into two well-defined lineages. The eleven C. closterium isolates formed a lineage and all clades were supported strongly. Statistical comparisons of SSU rDNA indicated that the average distance within lineageⅠwas significantly higher than that of other microalgae species (P 〈0.01). These results suggested the existence of cryptic species within C. closterium.
文摘A press conference was held in Beijing on August 23,marking the launch of a public competitive campaign to obtain a name and logo for China’s Mars mission.The project and its progress were introduced at the conference and the external appearance of the Mars probe and the rover was revealed.China’s Mars mission will be implemented in two steps.The objective of the first step is to achieve orbiting,landing,and roving.Mars sampling will be the purpose of the second step。
文摘OBJECTIVE: To study glomerular expression of C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha and beta (MIP-1alpha, MIP-1beta) and the effect of steroid and cyclophosphamide (CTX) intermittent intravenous pulse therapy on expression in patients with crescentic glomerulonephritis (CGN) to further investigate the underlying mechanism of the treatment. METHODS: Twelve patients with initial biopsy-proven CGN(2), 6 with lupus nephritis (lupus-CGN, LN-CGN) and 6 with vasculitis, (vasculitis-CGN, V-CGN) were enrolled in this study. They underwent an initial biopsy before steroid and CTX intermittent intravenous pulse therapy and were biopsied again one to three months later. Expression of MCP-1, MIP-1alpha, MIP-1beta, and CD68 in glomeruli with cellular and fibrocellular crescents were examined by immunohistochemical analysis in serial sections of renal biopsies. The effect of the pulse therapy on histopathological changes was also observed. RESULTS: Although steroid and CTX intermittent intravenous pulse therapy markedly reduced the degree of glomerular crescent formation both in LN-CGN and V-CGN, the effect of the therapy on glomerular chemokine expression was significantly different between LN-CGN and V-CGN. It was found that steroid and CTX intermittent intravenous pulse therapy reduced the expression of CD68, MCP-1, and MIP-1alpha, but had no effect on MIP-1beta in glomeruli with cellular crescents of patients with LN-CGN. In patients with V-CGN, the therapy also reduced the expression of CD68, but had no effect on MCP-1, MIP-1alpha, and MIP-1beta in glomeruli with cellular crescents. It was noted that the degree of glomerulosclerosis and tubular interstitial fibrosis increased more significantly at the second biopsy in V-CGN as compared to LN-CGN. CONCLUSIONS: The efficacy of steroid and CTX intermittent intravenous pulse therapy in CGN might be affected by reduction of glomerular chemokine expression. The different changes in glomerular expression of MCP-1 and MIP-1alpha in patients with LN-CGN and V-CGN after pulse therapy may correlate to different responses to treatment and prognosis.
文摘Objective To study the significance and distribution of renal infiltrating cells, including monocytes (CD68+ cells), proliferative cell nuclear antigen positive cells (PCNA+ cells), CD4+ and CD8+ cells in diffuse crescent glomerulonephritis (DCGN). Methods Fifty-six patients with DCGN were studied, including 10 cases of anti-glomerular basement membrane (GBM)-type Ⅰ DCGN, 26 immune complex-type Ⅱ DCGN, and 20 cases of pauci-immune-type Ⅲ DCGN. Glomerular and interstitial infiltrates of CD68+ and PCNA+ cells, and interstitial infiltrates of CD4+ and CD8+ cells were detected by using four-layer PAP methods. Results There was a significant increase of renal infiltrating CD68+, PCNA+, CD4+ and CD8+ cells in patients with DCGN compared with that in normal controls. In patients with type Ⅰ DCGN, there was a higher number of renal infiltrating CD68+ and PCNA+ cells than that in patients with type Ⅱ and Ⅲ DCGN. A glomerular infiltrates of CD68+ and PCNA+ cells correlated with the interstitial infiltrates of CD4+ cells in type Ⅰ or Ⅲ DCGN patients. In lupus DCGN patients, the numbers of renal infiltrating CD68+ and PCNA+ cells were similar to vasculitis or type Ⅲ DCGN patients.Conclusion These findings demonstrate that the renal infiltrates of CD68+ and PCNA+ cells play an important role in patients with DCGN, that the infiltrates of CD4+ cells correlate with the infiltrates of CD68+ and PCNA+ cells may be an active marker of DCGN, and that cell-mediated immunity may contribute to crescent formation in lupus DCGN patients.
基金supported by the National Basic Research Development of China(Grant No.2007CB407203)the National Scientific&Technical Basic Work Program(Grant No.2006FY110800)+1 种基金the National Natural Science Foundation of China(Grant No.49971013)the Gansu Provincial Natural Science Foundation(Grant No.0710RJZH084)
文摘Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and albedo between crescent sand ridges and tongue-shaped dunes,and between windward and leeward slopes of tongue-shaped dunes,result in their feathery appearance in aerial and satellite imagery.Measurements of the sand drift potential in the region show that the sand-moving wind for feathered sand ridges can be divided into three sectors;i.e.north-northeasterly,easterly and east-northeasterly sectors roughly corresponding to the southeast,northwest and southwest slip faces.Our findings suggests that the crescent sand ridges resulting from the connection of barchan dunes along the prevailing wind direction are longitudinal dune ridges rather than transverse ones.Tongue-shaped dunes and quasi-dune shapes have obvious distinctions and are new transverse dune types.According to McKee's dune shape classification,the feathered sand ridges are not a deformation dune type but a complex one.According to Wu's dune morphological and genetic classification,they are not dune ridges or compound dune ridges that form under the action of unidirectional winds or two winds intersecting at an acute angle,but are complex dune ridges that form under the action of three winds intersecting at an acute angle.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LQ16H120002)
文摘Objective: To assess the lower tear meniscus height(LTMH), central tear film thickness(CTFT), and central corneal epithelial thickness(CCET) after deep anterior lamellar keratoplasty(DALK). Methods: This was a retrospective cross-sectional study of 20 patients who had DALK in one eye over a three-month period. LTMH, CTFT, and CCET of the operated eyes and the unoperated fellow eyes were measured using high-definition optical coherence tomography(HD-OCT). Correlations between three OCT assessments and age, time following surgery, graft size, bed size, and the number of residual sutures were analyzed. Results: Compared to patients with keratoconus, patients with other corneal conditions had significantly higher CCET in the fellow eye(P=0.024). For all patients, CCET in the operated eye was significantly negatively correlated with the number of residual sutures(R=-0.579, P=0.008), and was significantly positively correlated with time following surgery(R=0.636, P=0.003). In the fellow eye, a significant positive correlation was found between age and CCET(R=0.551, P=0.012), and a significant negative correlation between age and CTFT(R=-0.491, P=0.028). LTMH was found to be significantly correlated between operated and fellow eyes(R=0.554, P=0.011). There was no significant correlation between LTMH and age, bed/graft size, time following surgery, or residual sutures(all possible correlations, P0.05). Conclusions: Patients with keratoconus tend to have a thinner central corneal epithelium. Corneal epithelium keeps regenerating over time after DALK. DALK did not induce a significant change in tear volume compared with the fellow eye. Postoperative tear function might depend on an individual's general condition, rather than on age, gender, bed/graft size, time following surgery, or residual sutures.
基金supported by the National Natural Science Foundation of China(Grant Nos.11272252 and 11102153)
文摘The migration of a downsized crescent-shaped dune was investigated in a wind tunnel experiment.Quantified upwind influx and vertical oscillation of the sand bed were introduced to modulate the saturation level of the sand flux above the dune surface to affect dune evolution.The evolution was recorded by top-view photography and then abstracted as the evolution of self-defined characteristic quantities using a digital image processing algorithm.The results showed that,in contrast to the case for spanwise quantities,the evolution of streamwise quantities corresponds to a linear increase in the modulation magnitude more positively and in a monotonic and convergent manner.In contrast with quantities on the windward face,the changes in quantities with respect to the horns were nonmonotonic with time and almost uncorrelated with the variation in modulation strength,which reveals the distinctiveness of leeside evolution.