BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an ...BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an essential physiological process that occurs during embryonic development and tissue regeneration.Angiogenesis is the growth of new capillaries from pre-existing blood vessels,which is observed both prenatally and postnatally.The placenta is an organ composed of a variety of fetal-derived cells,including ECFCs,and therefore has significant potential as a source of fetal ECFCs for tissue engineering.AIM To investigate the possibility of isolating clonal ECFCs from human early gestation chorionic villi(CV-ECFCs)of the placenta,and assess their potential for tissue engineering.METHODS The early gestation chorionic villus tissue was dissociated by enzyme digestion.Cells expressing CD31 were selected using magnetic-activated cell sorting,and plated in endothelial-specific growth medium.After 2-3 wks in culture,colonies displaying cobblestone-like morphology were manually picked using cloning cylinders.We characterized CV-ECFCs by flow cytometry,immunophenotyping,tube formation assay,and Dil-Ac-LDL uptake assay.Viral transduction of CVECFCs was performed using a Luciferase/tdTomato-containing lentiviral vector,and transduction efficiency was tested by fluorescent microscopy and flow cytometry.Compatibility of CV-ECFCs with a delivery vehicle was determined using an FDA approved,small intestinal submucosa extracellular matrix scaffold.RESULTS After four passages in 6-8 wks of culture,we obtained a total number of 1.8×107 CV-ECFCs using 100 mg of early gestational chorionic villus tissue.Immunophenotypic analyses by flow cytometry demonstrated that CV-ECFCs highly expressed the endothelial markers CD31,CD144,CD146,CD105,CD309,only partially expressed CD34,and did not express CD45 and CD90.CV-ECFCs were capable of acetylated low-density lipoprotein uptake and tube formation,similar to cord blood-derived ECFCs(CB-ECFCs).CV-ECFCs can be transduced with a Luciferase/tdTomato-containing lentiviral vector at a transduction efficiency of 85.1%.Seeding CV-ECFCs on a small intestinal submucosa extracellular matrix scaffold confirmed that CV-ECFCs were compatible with the biomaterial scaffold.CONCLUSION In summary,we established a magnetic sorting-assisted clonal isolation approach to derive CV-ECFCs.A substantial number of CV-ECFCs can be obtained within a short time frame,representing a promising novel source of ECFCs for fetal treatments.展开更多
The organization of the compartment of mesenchymal stem cells is still obscure. Two types of human stromal precursor cells are known. Both of them are analyzed in in vitro system: mesenchymal multipotent stromal cells...The organization of the compartment of mesenchymal stem cells is still obscure. Two types of human stromal precursor cells are known. Both of them are analyzed in in vitro system: mesenchymal multipotent stromal cells (MMSC) and fibroblast colony forming units (CFU-F). The aim of this study was to compare the main characteristics of MMSC and CFU-F derived from the bone marrow of 24 healthy donors. Growth and differentiation parameters, as well as relative expression levels of different genes were analyzed in MMSC and CFU-F. MMSC were cultivated for 5 passages. CFU-F concentration was determined for each bone marrow sample. The data obtained demonstrated the heterogeneity and hierarchical organization of both studied populations of stromal precursor cells-MMSC and CFU-F. These two types of stromal precursor cells turned to be different in most parameters studied. Altogether MMSC seemed to be more immature cells than CFU-F and took up the higher position in hierarchical tree of mesenchymal stem cells. The rate of differentiation and proliferative potential decreased with the donor’s age in both populations MMSC and CFU-F.展开更多
Human cytomegalovirus （HCMV） late mRNA expression in megakaryoblast and in turn the pathogenesis of idiopathic thrombocytopenic purpura （ITP） patients with HCMV infection, and effectiveness of ganciclovir were inv...Human cytomegalovirus （HCMV） late mRNA expression in megakaryoblast and in turn the pathogenesis of idiopathic thrombocytopenic purpura （ITP） patients with HCMV infection, and effectiveness of ganciclovir were investigated. Colony forming unit-megakaryocytes （CFU-MK） of 46 ITP patients with HCMV infection were incubated from patients＇ bone marrow mononuclear cells （MNC）. Reverse transcriptase-polymerase chain reaction （RT-PCR） was subsequently used for CFU-MK for HCMV-late mRNA detection, Ganciclovir therapy was given to both HCMV-late mRNA positive and negative groups for comparison of therapeutic effectiveness, The results in 19 of 46 CFU-MK culture cells specimens with positive HCMV-DNA by PCR or positive CMV-IgM by enzyme linked immunosorbent assay （ELISA） in the correspondent serum of peripheral blood were positive for HCMV-late mRNA, Sixteen out of 19 patients with positive HCMV-late mRNA CFU-MK had a positive response to ganciclovir. Amongst 27 patients with negative HCMV-late mRNA CFU-MK, only 4 positive responders to ganciclovir therapy were observed. Curative effectiveness of ganciclovir in HCMV-late mRNA positive group was significantly higher than that in HCMV-late mRNA negative group （P〈0.01）, It was suggested that HCMV could directly infect CFU-MK, which might be one of the mechanisms responsible for HCMV related ITE The ganci- clovir is an effective therapy in resulting in the increases in thrombocyte in the ITP patients whose HCMV- late mRNA was positive in their CFU-MK.展开更多
As one of the most widely used assays in biological research,an enumeration of the bacterial cell colonies is an important but time-consuming and labor-intensive process.To speed up the colony counting,a machine learn...As one of the most widely used assays in biological research,an enumeration of the bacterial cell colonies is an important but time-consuming and labor-intensive process.To speed up the colony counting,a machine learning method is presented for counting the colony forming units(CFUs),which is referred to as CFUCounter.This cellcounting program processes digital images and segments bacterial colonies.The algorithm combines unsupervised machine learning,iterative adaptive thresholding,and local-minima-based watershed segmentation to enable an accurate and robust cell counting.Compared to a manual counting method,CFUCounter supports color-based CFU classification,allows plates containing heterologous colonies to be counted individually,and demonstrates overall performance(slope 0.996,SD 0.013,95%CI:0.97–1.02,p value<1e-11,r=0.999)indistinguishable from the gold standard of point-and-click counting.This CFUCounter application is open-source and easy to use as a unique addition to the arsenal of colony-counting tools.展开更多
目的探讨微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病(ALL)大剂量化疗后患者粒细胞集落刺激因子受体(G-CSFR)、粒单系集落形成单位(CFU-GM)、肠道菌群及红系爆式集落形成单位(BFU-E)的影响。方法选取延安大学附属医院2019年6月至2022...目的探讨微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病(ALL)大剂量化疗后患者粒细胞集落刺激因子受体(G-CSFR)、粒单系集落形成单位(CFU-GM)、肠道菌群及红系爆式集落形成单位(BFU-E)的影响。方法选取延安大学附属医院2019年6月至2022年12月收治的ALL患者130例作为研究对象,根据治疗方法将患者分为A组、B组、C组,3组患者均接受大剂量化疗,化疗结束48 h后A组患者实施常规治疗,B组患者单纯浙贝黄芩汤治疗,C组给予微生态制剂联合浙贝黄芩汤治疗,治疗12 d后,对3组患者G-CSFR、CFU-GM、BFU-E表达情况及血细胞数量进行检测。结果治疗后,C组血红蛋白、白细胞、血小板[(79±6)g/L、(3.8±0.4)×10^(9)/L、(66.4±3.6)×10^(9)/L]与A组[(59±7)g/L、(3.2±0.4)×10^(9)/L、(52.6±2.8)×10^(9)/L]、B组[(61±7)g/L、(3.1±0.3)×10^(9)/L、(52.8±2.6)×10^(9)/L]对比,差异有统计学意义(P<0.05)。C组G-CSFR(5.35±0.16)pg/ml和白细胞介素-11受体(IL-11R)(6.38±0.54)μg/kg水平均高于A组[(2.23±0.13)pg/ml和(1.49±0.24)μg/kg]和B组[(2.31±0.16)pg/ml和(2.31±0.49)μg/kg]差异有统计学意义(P<0.05)。治疗后,C组患者7 d CFU-GM(18.5±6.0)个和14 d BFU-E(83.5±7.5)个高于A组[7 d CFU-GM(9.5±2.0)个和14 d BFU-E(59.5±6.5)个]和B组[7 d CFU-GM(12.0±6.5)个和14 d BFU-E(63.5±5.0)个],差异有统计学意义(P<0.05)。7 d后,C组双歧杆菌(12.56±3.25)lgCFU/g、乳酸杆菌(13.56±2.58)lgCFU/g、肠杆菌(5.12±1.45)lgCFU/g、肠球菌(5.14±0.58)lgCFU/g高于A组[(9.26±1.03)lg CFU/g、(8.65±0.84)lg CFU/g、(8.08±0.64)lgCFU/g、(8.15±0.46)lgCFU/g]和B组[(11.35±1.36)lg CFU/g、(12.43±1.14)lgCFU/g、(6.49±0.55)lgCFU/g、(6.66±0.43)lgCFU/g],差异有统计学意义(P<0.05)。结论微生态制剂联合浙贝黄芩汤治疗可以有效提高ALL大剂量化疗后患者的G-CSFR、CFU-GM、BFU-E水平,可能更好地改善化疗引起的患者骨髓抑制情况,改善肠道菌群,具有临床研究价值。展开更多
Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize(Zea mays L....Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize(Zea mays L.). The extent of systemic colonization of F. verticillioides in roots from maize lines either resistant or susceptible to the fungus was studied by visualizing the red fluorescence produced by the fungus expressing DsRed. The difference in quantities of colony forming units(CFU) in roots and basal stems, production of fumonisin B1, and pH of root were determined. Although F. verticillioides colonized both resistant and susceptible lines, differences were observed in the pattern and extent of fungal colonization in the two types of maize lines. The fungus colonized the susceptible lines producing mosaic patterns by filling the individual root cells with hyphae. Such a pattern of colonization was rarely observed in resistant lines, which were less colonized by the fungus than the susceptible lines in terms of CFUs. The production of mycotoxin fumonisin B1 in roots from different lines was closely correlated with the amount of F. verticillioides colonization, rather than the pH or amylopectin concentrations in the root. The findings from this study contribute to a better understanding of the defense mechanism in resistant maize lines to F. verticillioides.展开更多
Background: Due to their delicious taste, high nutritional content, and health benefits, fruit juices are well-known drinks in many countries and are now an essential component of the modern diet. Objective: Determini...Background: Due to their delicious taste, high nutritional content, and health benefits, fruit juices are well-known drinks in many countries and are now an essential component of the modern diet. Objective: Determining the microbiological quality of both packaged and freshly made fruit and milk juices. Method: The spread-plate approach was employed to isolate and count the bacteria. 90 ml of sterile peptone water were blended with 10 ml of well-mixed, packed, and freshly made fruit juices. The samples were sequentially diluted (101 - 105) in accordance with the Indian Manual of Food Microbiological Testing Methods. Results: From eight samples of imported packaged fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 1.39 × 102, and 2 × 102 CFU/ml, respectively. In contrast, from three samples of locally produced fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 5.83 × 102, and 2.73 × 103 CFU/ml, respectively. Four samples of handmade prepared fruit and milk juices had a mean of total coliform, staphylococci, and viable bacterial count of 1.441 × 104, 4.1 × 103, and 2.35 × 105 CFU/ml, respectively. Conclusion: 33.3% of the results from microbiological analysis of freshly made fruit and milk juices met the permissible range of the Revised Microbiological Standards for Fruit and Vegetables and Their Products, which were published in 2018 and as well as the Hong Kong Center for Food Safety, whereas 66.7% of the microbiological analyses of freshly prepared fruit and milk juices were above the permissible reference range of GSO standard 2000. 12.5% of the investigated imported and packed fruits and milk juices had one failed test (TSC), which was above the acceptable limit, 87.5% of the tested samples of fruit and milk juices fulfilled the necessary standards of TCC, TVBC, and TSC. 100% of the tested locally manufactured fruit and milk juices complied with TSC, TCC, and TVBC requirements. All investigations showed that freshly made fruit and milk juices were heavily contaminated (Total viable bacterial count, total coliform count, and total staphylococcus count). .展开更多
To confirm the existence of hepatic stem cells (HSCs), fetal liver cells isolated from mice on embryonic day 13 (ED13) were long-term cultured in vitro. Growth of the cells was observed intensively and characteristics...To confirm the existence of hepatic stem cells (HSCs), fetal liver cells isolated from mice on embryonic day 13 (ED13) were long-term cultured in vitro. Growth of the cells was observed intensively and characteristics were iden-tified by immunocytochemistry. The results showed that some of the cells grew as colonies, in which some cells ex-pressed AFP, CD34 and Albumin. Then the cells were trans-planted intravenously into irradiated syngeneic mice. At day 12 a number of small hyperplasia nodules were seen in the apparently enlarged spleens of recipient mice. Moreover, some nodules were positive for AFP and CD34 and consisted of various types of cells, suggesting the very existence of he-patic stem cells in the mouse fetal liver.展开更多
Most probable number （MPN） and colony-forming unit （CFU） estimates of fecal indicator bacteria （FIB） concentration are common measures of water quality in aquatic environments. Thus, FIB intensively monitored in...Most probable number （MPN） and colony-forming unit （CFU） estimates of fecal indicator bacteria （FIB） concentration are common measures of water quality in aquatic environments. Thus, FIB intensively monitored in Yeongsan Watershed in an attempt to compare two different methods and to develop a statistical model to convert from CFU to MPN estimates or vice versa. As a result, the significant difference was found in the MPN and CFU estimates. The enumerated Escherichia coli concentrations in MPN are greater than those in CFU, except for the measurement in winter. Especially in fall, E. coli concentrations in MPN are one order of magnitude greater than that in CFU. Contrarily, enterococci bacteria in MPN are lower than those in CFU. However, in general, a strongly positive relationship are found between MPN and CFU estimates. Therefore, the statistical models were developed, and showed the reasonable converting FIB concentrations from CFU estimates to MPN estimates. We expect this study will provide preliminary information towards future research on whether different analysis methods may result in different water quality standard violation frequencies for the same water sample.展开更多
基金the Shriners Hospital for Children Postdoctoral Research Fellowship award,No.84704-NCA-19UC Davis School of Medicine Dean’s Fellowship award and funding from the NIH,No.5R01NS100761-02 and No.R03HD091601-01+2 种基金the California Institute of Regenerative Medicine,No.PC1-08103 and No.CLIN1-11404Shriners Hospitals for Children,No.85120-NCA-16,No.85119-NCA-18,No.85108-NCA-19 and No.87200-NCA-19March of Dimes Foundation,No.5FY1682
文摘BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an essential physiological process that occurs during embryonic development and tissue regeneration.Angiogenesis is the growth of new capillaries from pre-existing blood vessels,which is observed both prenatally and postnatally.The placenta is an organ composed of a variety of fetal-derived cells,including ECFCs,and therefore has significant potential as a source of fetal ECFCs for tissue engineering.AIM To investigate the possibility of isolating clonal ECFCs from human early gestation chorionic villi(CV-ECFCs)of the placenta,and assess their potential for tissue engineering.METHODS The early gestation chorionic villus tissue was dissociated by enzyme digestion.Cells expressing CD31 were selected using magnetic-activated cell sorting,and plated in endothelial-specific growth medium.After 2-3 wks in culture,colonies displaying cobblestone-like morphology were manually picked using cloning cylinders.We characterized CV-ECFCs by flow cytometry,immunophenotyping,tube formation assay,and Dil-Ac-LDL uptake assay.Viral transduction of CVECFCs was performed using a Luciferase/tdTomato-containing lentiviral vector,and transduction efficiency was tested by fluorescent microscopy and flow cytometry.Compatibility of CV-ECFCs with a delivery vehicle was determined using an FDA approved,small intestinal submucosa extracellular matrix scaffold.RESULTS After four passages in 6-8 wks of culture,we obtained a total number of 1.8×107 CV-ECFCs using 100 mg of early gestational chorionic villus tissue.Immunophenotypic analyses by flow cytometry demonstrated that CV-ECFCs highly expressed the endothelial markers CD31,CD144,CD146,CD105,CD309,only partially expressed CD34,and did not express CD45 and CD90.CV-ECFCs were capable of acetylated low-density lipoprotein uptake and tube formation,similar to cord blood-derived ECFCs(CB-ECFCs).CV-ECFCs can be transduced with a Luciferase/tdTomato-containing lentiviral vector at a transduction efficiency of 85.1%.Seeding CV-ECFCs on a small intestinal submucosa extracellular matrix scaffold confirmed that CV-ECFCs were compatible with the biomaterial scaffold.CONCLUSION In summary,we established a magnetic sorting-assisted clonal isolation approach to derive CV-ECFCs.A substantial number of CV-ECFCs can be obtained within a short time frame,representing a promising novel source of ECFCs for fetal treatments.
文摘The organization of the compartment of mesenchymal stem cells is still obscure. Two types of human stromal precursor cells are known. Both of them are analyzed in in vitro system: mesenchymal multipotent stromal cells (MMSC) and fibroblast colony forming units (CFU-F). The aim of this study was to compare the main characteristics of MMSC and CFU-F derived from the bone marrow of 24 healthy donors. Growth and differentiation parameters, as well as relative expression levels of different genes were analyzed in MMSC and CFU-F. MMSC were cultivated for 5 passages. CFU-F concentration was determined for each bone marrow sample. The data obtained demonstrated the heterogeneity and hierarchical organization of both studied populations of stromal precursor cells-MMSC and CFU-F. These two types of stromal precursor cells turned to be different in most parameters studied. Altogether MMSC seemed to be more immature cells than CFU-F and took up the higher position in hierarchical tree of mesenchymal stem cells. The rate of differentiation and proliferative potential decreased with the donor’s age in both populations MMSC and CFU-F.
文摘Human cytomegalovirus （HCMV） late mRNA expression in megakaryoblast and in turn the pathogenesis of idiopathic thrombocytopenic purpura （ITP） patients with HCMV infection, and effectiveness of ganciclovir were investigated. Colony forming unit-megakaryocytes （CFU-MK） of 46 ITP patients with HCMV infection were incubated from patients＇ bone marrow mononuclear cells （MNC）. Reverse transcriptase-polymerase chain reaction （RT-PCR） was subsequently used for CFU-MK for HCMV-late mRNA detection, Ganciclovir therapy was given to both HCMV-late mRNA positive and negative groups for comparison of therapeutic effectiveness, The results in 19 of 46 CFU-MK culture cells specimens with positive HCMV-DNA by PCR or positive CMV-IgM by enzyme linked immunosorbent assay （ELISA） in the correspondent serum of peripheral blood were positive for HCMV-late mRNA, Sixteen out of 19 patients with positive HCMV-late mRNA CFU-MK had a positive response to ganciclovir. Amongst 27 patients with negative HCMV-late mRNA CFU-MK, only 4 positive responders to ganciclovir therapy were observed. Curative effectiveness of ganciclovir in HCMV-late mRNA positive group was significantly higher than that in HCMV-late mRNA negative group （P〈0.01）, It was suggested that HCMV could directly infect CFU-MK, which might be one of the mechanisms responsible for HCMV related ITE The ganci- clovir is an effective therapy in resulting in the increases in thrombocyte in the ITP patients whose HCMV- late mRNA was positive in their CFU-MK.
基金This research was funded by a VPR Special Research Grant entitled Potential of a Site-Specific DNA Interstrand Crosslink.
文摘As one of the most widely used assays in biological research,an enumeration of the bacterial cell colonies is an important but time-consuming and labor-intensive process.To speed up the colony counting,a machine learning method is presented for counting the colony forming units(CFUs),which is referred to as CFUCounter.This cellcounting program processes digital images and segments bacterial colonies.The algorithm combines unsupervised machine learning,iterative adaptive thresholding,and local-minima-based watershed segmentation to enable an accurate and robust cell counting.Compared to a manual counting method,CFUCounter supports color-based CFU classification,allows plates containing heterologous colonies to be counted individually,and demonstrates overall performance(slope 0.996,SD 0.013,95%CI:0.97–1.02,p value<1e-11,r=0.999)indistinguishable from the gold standard of point-and-click counting.This CFUCounter application is open-source and easy to use as a unique addition to the arsenal of colony-counting tools.
文摘目的探讨微生态制剂联合浙贝黄芩汤对急性淋巴细胞白血病(ALL)大剂量化疗后患者粒细胞集落刺激因子受体(G-CSFR)、粒单系集落形成单位(CFU-GM)、肠道菌群及红系爆式集落形成单位(BFU-E)的影响。方法选取延安大学附属医院2019年6月至2022年12月收治的ALL患者130例作为研究对象,根据治疗方法将患者分为A组、B组、C组,3组患者均接受大剂量化疗,化疗结束48 h后A组患者实施常规治疗,B组患者单纯浙贝黄芩汤治疗,C组给予微生态制剂联合浙贝黄芩汤治疗,治疗12 d后,对3组患者G-CSFR、CFU-GM、BFU-E表达情况及血细胞数量进行检测。结果治疗后,C组血红蛋白、白细胞、血小板[(79±6)g/L、(3.8±0.4)×10^(9)/L、(66.4±3.6)×10^(9)/L]与A组[(59±7)g/L、(3.2±0.4)×10^(9)/L、(52.6±2.8)×10^(9)/L]、B组[(61±7)g/L、(3.1±0.3)×10^(9)/L、(52.8±2.6)×10^(9)/L]对比,差异有统计学意义(P<0.05)。C组G-CSFR(5.35±0.16)pg/ml和白细胞介素-11受体(IL-11R)(6.38±0.54)μg/kg水平均高于A组[(2.23±0.13)pg/ml和(1.49±0.24)μg/kg]和B组[(2.31±0.16)pg/ml和(2.31±0.49)μg/kg]差异有统计学意义(P<0.05)。治疗后,C组患者7 d CFU-GM(18.5±6.0)个和14 d BFU-E(83.5±7.5)个高于A组[7 d CFU-GM(9.5±2.0)个和14 d BFU-E(59.5±6.5)个]和B组[7 d CFU-GM(12.0±6.5)个和14 d BFU-E(63.5±5.0)个],差异有统计学意义(P<0.05)。7 d后,C组双歧杆菌(12.56±3.25)lgCFU/g、乳酸杆菌(13.56±2.58)lgCFU/g、肠杆菌(5.12±1.45)lgCFU/g、肠球菌(5.14±0.58)lgCFU/g高于A组[(9.26±1.03)lg CFU/g、(8.65±0.84)lg CFU/g、(8.08±0.64)lgCFU/g、(8.15±0.46)lgCFU/g]和B组[(11.35±1.36)lg CFU/g、(12.43±1.14)lgCFU/g、(6.49±0.55)lgCFU/g、(6.66±0.43)lgCFU/g],差异有统计学意义(P<0.05)。结论微生态制剂联合浙贝黄芩汤治疗可以有效提高ALL大剂量化疗后患者的G-CSFR、CFU-GM、BFU-E水平,可能更好地改善化疗引起的患者骨髓抑制情况,改善肠道菌群,具有临床研究价值。
基金the National Natural Science Foundation (31170080)China Agricultural Research Service (CARS-02) was greatly appreciated
文摘Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize(Zea mays L.). The extent of systemic colonization of F. verticillioides in roots from maize lines either resistant or susceptible to the fungus was studied by visualizing the red fluorescence produced by the fungus expressing DsRed. The difference in quantities of colony forming units(CFU) in roots and basal stems, production of fumonisin B1, and pH of root were determined. Although F. verticillioides colonized both resistant and susceptible lines, differences were observed in the pattern and extent of fungal colonization in the two types of maize lines. The fungus colonized the susceptible lines producing mosaic patterns by filling the individual root cells with hyphae. Such a pattern of colonization was rarely observed in resistant lines, which were less colonized by the fungus than the susceptible lines in terms of CFUs. The production of mycotoxin fumonisin B1 in roots from different lines was closely correlated with the amount of F. verticillioides colonization, rather than the pH or amylopectin concentrations in the root. The findings from this study contribute to a better understanding of the defense mechanism in resistant maize lines to F. verticillioides.
文摘Background: Due to their delicious taste, high nutritional content, and health benefits, fruit juices are well-known drinks in many countries and are now an essential component of the modern diet. Objective: Determining the microbiological quality of both packaged and freshly made fruit and milk juices. Method: The spread-plate approach was employed to isolate and count the bacteria. 90 ml of sterile peptone water were blended with 10 ml of well-mixed, packed, and freshly made fruit juices. The samples were sequentially diluted (101 - 105) in accordance with the Indian Manual of Food Microbiological Testing Methods. Results: From eight samples of imported packaged fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 1.39 × 102, and 2 × 102 CFU/ml, respectively. In contrast, from three samples of locally produced fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 5.83 × 102, and 2.73 × 103 CFU/ml, respectively. Four samples of handmade prepared fruit and milk juices had a mean of total coliform, staphylococci, and viable bacterial count of 1.441 × 104, 4.1 × 103, and 2.35 × 105 CFU/ml, respectively. Conclusion: 33.3% of the results from microbiological analysis of freshly made fruit and milk juices met the permissible range of the Revised Microbiological Standards for Fruit and Vegetables and Their Products, which were published in 2018 and as well as the Hong Kong Center for Food Safety, whereas 66.7% of the microbiological analyses of freshly prepared fruit and milk juices were above the permissible reference range of GSO standard 2000. 12.5% of the investigated imported and packed fruits and milk juices had one failed test (TSC), which was above the acceptable limit, 87.5% of the tested samples of fruit and milk juices fulfilled the necessary standards of TCC, TVBC, and TSC. 100% of the tested locally manufactured fruit and milk juices complied with TSC, TCC, and TVBC requirements. All investigations showed that freshly made fruit and milk juices were heavily contaminated (Total viable bacterial count, total coliform count, and total staphylococcus count). .
基金This work was supported bythe program issued by the Ministry of Science and Technology of China (Grant No. TJ99-LA01) the Program for Backbone College Teachers issued by the Ministry of Education of China.
文摘To confirm the existence of hepatic stem cells (HSCs), fetal liver cells isolated from mice on embryonic day 13 (ED13) were long-term cultured in vitro. Growth of the cells was observed intensively and characteristics were iden-tified by immunocytochemistry. The results showed that some of the cells grew as colonies, in which some cells ex-pressed AFP, CD34 and Albumin. Then the cells were trans-planted intravenously into irradiated syngeneic mice. At day 12 a number of small hyperplasia nodules were seen in the apparently enlarged spleens of recipient mice. Moreover, some nodules were positive for AFP and CD34 and consisted of various types of cells, suggesting the very existence of he-patic stem cells in the mouse fetal liver.
基金supported by the Korean Ministry of Environment as "The Eco-technopia 21 Project" (No. 019-071-053)
文摘Most probable number （MPN） and colony-forming unit （CFU） estimates of fecal indicator bacteria （FIB） concentration are common measures of water quality in aquatic environments. Thus, FIB intensively monitored in Yeongsan Watershed in an attempt to compare two different methods and to develop a statistical model to convert from CFU to MPN estimates or vice versa. As a result, the significant difference was found in the MPN and CFU estimates. The enumerated Escherichia coli concentrations in MPN are greater than those in CFU, except for the measurement in winter. Especially in fall, E. coli concentrations in MPN are one order of magnitude greater than that in CFU. Contrarily, enterococci bacteria in MPN are lower than those in CFU. However, in general, a strongly positive relationship are found between MPN and CFU estimates. Therefore, the statistical models were developed, and showed the reasonable converting FIB concentrations from CFU estimates to MPN estimates. We expect this study will provide preliminary information towards future research on whether different analysis methods may result in different water quality standard violation frequencies for the same water sample.
