The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to ...The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to a diverse and rapidly expanding list of economically important filamentous fungi and oomycetes. With the significant number of fungal genomes now sequenced or being sequenced, functional genomics promises to uncover a great deal of new information in coming years. This review discusses recent advances that have been made in examining gene function in filamentous fungi and describes the advantages and limitations of the different approaches.展开更多
Among 27 filamentous fungi, a strain Aspergillus niger An76 gave the highest siderophore yield even when cultured on natural medium or minimal medium containing 1 mmol L^-1 Fe^3＋. Whereas for most other strains, the ...Among 27 filamentous fungi, a strain Aspergillus niger An76 gave the highest siderophore yield even when cultured on natural medium or minimal medium containing 1 mmol L^-1 Fe^3＋. Whereas for most other strains, the capacities of siderophore production was repressed as the concentrations of Fe^3＋ was higher than 20 ~tmol L^-1. Lower ferric iron concentrations were more conducive to siderophore synthesis for those strains. The An76 siderophore was partially purified through a series of chromatography steps using Sephadex LH20 and CM-Sepharose Fast Flow columns. Its structural characteristics differed from typical siderophores, such as catecholates or hydroxamates, and no amino acids or peptide bonds were detected. It may therefore represent a new type of siderophore structure. TBA assay and ESR trapping studies showed that An76 siderophore had remarkable scavenging activity of hydroxyl free radicals in vitro. The antibiotic activities of siderophores produced by An76 were tested against 29 bacterial strains, including plant, animal, and human pathogens. The growth of 14 bacterial strains could be completely inhibited at a siderophore concentration of 8 mg ml^-1 with an incubation time of 30 min. Evidence suggests that the An76 siderophore has potential value as an antioxidant and a biocontrol agent against pathogenic microorganisms.展开更多
The wall shear stress （WSS） that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology （e.g. angiogenesis） and af...The wall shear stress （WSS） that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology （e.g. angiogenesis） and affects the microvasculature＇s primary function of molecular transport. Points of fluctuating WSS show abnormalities in a number of diseases; however, there is no established technique for measuring WSS directly in physiological systems. All current methods rely on estimates obtained from measured velocity gradients in bulk flow data. In this work, we report a nanosensor that can directly measure WSS in microfluidic chambers with sub-micron spatial resolution by using a specific type of virus, the bacteriophage M13, which has been fluorescently labeled and anchored to a surface. It is demonstrated that the nanosensor can be calibrated and adapted for biological tissue, revealing WSS in micro-domains of cells that cannot be calculated accurately from bulk flow measurements. This method lends itself to a platform applicable to many applications in biology and microfluidics.展开更多
文摘The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to a diverse and rapidly expanding list of economically important filamentous fungi and oomycetes. With the significant number of fungal genomes now sequenced or being sequenced, functional genomics promises to uncover a great deal of new information in coming years. This review discusses recent advances that have been made in examining gene function in filamentous fungi and describes the advantages and limitations of the different approaches.
基金This work was supported by the National Natural Science Foundation of China （No. 30470051）, the Major State Basic Research Development Program of China （973, No. 2004CB7197）, and the Natural Science Foundation of Shandong Province （No. Y2004D07）.
文摘Among 27 filamentous fungi, a strain Aspergillus niger An76 gave the highest siderophore yield even when cultured on natural medium or minimal medium containing 1 mmol L^-1 Fe^3＋. Whereas for most other strains, the capacities of siderophore production was repressed as the concentrations of Fe^3＋ was higher than 20 ~tmol L^-1. Lower ferric iron concentrations were more conducive to siderophore synthesis for those strains. The An76 siderophore was partially purified through a series of chromatography steps using Sephadex LH20 and CM-Sepharose Fast Flow columns. Its structural characteristics differed from typical siderophores, such as catecholates or hydroxamates, and no amino acids or peptide bonds were detected. It may therefore represent a new type of siderophore structure. TBA assay and ESR trapping studies showed that An76 siderophore had remarkable scavenging activity of hydroxyl free radicals in vitro. The antibiotic activities of siderophores produced by An76 were tested against 29 bacterial strains, including plant, animal, and human pathogens. The growth of 14 bacterial strains could be completely inhibited at a siderophore concentration of 8 mg ml^-1 with an incubation time of 30 min. Evidence suggests that the An76 siderophore has potential value as an antioxidant and a biocontrol agent against pathogenic microorganisms.
文摘The wall shear stress （WSS） that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology （e.g. angiogenesis） and affects the microvasculature＇s primary function of molecular transport. Points of fluctuating WSS show abnormalities in a number of diseases; however, there is no established technique for measuring WSS directly in physiological systems. All current methods rely on estimates obtained from measured velocity gradients in bulk flow data. In this work, we report a nanosensor that can directly measure WSS in microfluidic chambers with sub-micron spatial resolution by using a specific type of virus, the bacteriophage M13, which has been fluorescently labeled and anchored to a surface. It is demonstrated that the nanosensor can be calibrated and adapted for biological tissue, revealing WSS in micro-domains of cells that cannot be calculated accurately from bulk flow measurements. This method lends itself to a platform applicable to many applications in biology and microfluidics.
