Flagella,the basic locomotive organ in algae,as well as bacteria and some cells of animals or high plants,would be damaged in the well stirred mass culture due to the strong forces caused by the fast mixing impellers....Flagella,the basic locomotive organ in algae,as well as bacteria and some cells of animals or high plants,would be damaged in the well stirred mass culture due to the strong forces caused by the fast mixing impellers. The dynamic regeneration of the flagella in deflagellated Dunaliella salina was studied microscopically by using a bench top flat bottom photobioreactor. The results showed that 90 minutes was necessary for the repair of flagella,after which half of the cells became motile as their flagella generated within 120 minutes and nearly all of the cells could swim freely within 180 minutes.展开更多
Nanomachines are controllable machines at the nano meter or molecular scale that are composed of nano-scale components.They have their own mechanochemistry,dynamics,workspace,and usability and are composed of nature&#...Nanomachines are controllable machines at the nano meter or molecular scale that are composed of nano-scale components.They have their own mechanochemistry,dynamics,workspace,and usability and are composed of nature's building blocks:namely proteins,DNA,and other compounds.Some bacteria(i.e.Escherichia coli)swim by rotating helical flagella.The structure and motion character of the flagellum are introduced.Through the study,a micro-robot was designed and its mechanical structure was explained in this paper.In the future,the bionic micro-robot is expected tobe built,which can travel inside the human body and carry out a host of complex operations such as minimally invasive surgery,highly localized drug delivery,and screening for diseases that are in their very early stages.It is important to medicine and could be applied in other areas,including space exploration,electronics and military.展开更多
MUC1, a tumor-associated antigen overexpressed in many carcinomas, represents a candidate of choice for cancer immunotherapy. Flagella-based MUC1 vaccines were tested in therapeutic setting in two aggressive breast ca...MUC1, a tumor-associated antigen overexpressed in many carcinomas, represents a candidate of choice for cancer immunotherapy. Flagella-based MUC1 vaccines were tested in therapeutic setting in two aggressive breast cancer models, comprising the implantation of the 4T1-MUC1 cell line in either Balb/c, or Human MUC1 transgenic mice in which spontaneous metastases occurs. Recombinant flagella carrying only 7 amino acid of MUC1 elicited therapeutic activity, affecting both the growth of established growing tumors and the number of metastases. Higher therapeutic activity was achieved with an additional recombinant flagella designed with the SYFPEITHI algorithm. The vaccines triggered a Th1 response against MUC1 with no evident autoimmune response towards healthy MUC1-expressing tissues. Recombinant flagella carrying a 25-residue fragment of MUC1, induced the most effective response, as evidenced by a significant reduction of both the size and growth rate of the tumor as well as by the lower number of metastases, and expanding life span of vaccinated mice.展开更多
Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most ani...Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most animal cells harbor cilia in contrast to very few fungal cells. While this was not unexpected, it was the position and arrangement of this organelle in each cell that intrigued our attention. Natural selection might have favored motility over chemotaxis;and it would have done so to evolve a stable structure that could have undergone an optimization process requiring a precise geometry in the shape of cells and the structure that would help cells to move. The positioning of such a structure would play a pre-dominant role in optimal motility. It is now known that the flagellar position of a cell is a genetically distinct trait, occasionally used in phylogeny of bacteria, distributed in distinguishing patterns over cellular surface, but basically are of two types, either polar (one flagellum arising from one pole per cell) or peritrichous (lateral flagella distributed over the entire cell surface). Irrespective of the cellular habitat, flagella origin, ultrastructure and proteome, the present investigation surveyed 26 sub-types of flagellar arrangements from as many species as possible. A peculiar pattern ensued-Prokaryotes harbored predominantly polar and peritrichous types;eukaryotes showed a mere change of the peritrichous one. These numbers when used to create a Similarity tree depicted a similarity distance of 14 between the Eubacteria and Archaebacteria forming the first neighborhood;Protozoans, Algae, Fungi, Plantae and Animalia formed a second neighborhood. We offer a working hypothesis for this pattern and the gradual shift in the flagellar arrangement from polar, peritrichous, sub-apical, and apical to lateral throughout evolution.展开更多
Rhodobacter sphaeroides 2.4.1 belongs to the?-3 subdivision of the Proteobacteria. It possesses a multipartite genome structure consisting of two circular chromosomes, andit displays a wide range of metabolic diversit...Rhodobacter sphaeroides 2.4.1 belongs to the?-3 subdivision of the Proteobacteria. It possesses a multipartite genome structure consisting of two circular chromosomes, andit displays a wide range of metabolic diversity.Approximately 40 flagellar proteins are required for structure, assembly, and regulation of the flagellum formation in most bacterial species. R. sphaeroidescontains two flagellar gene clusters (fla1 and fla2),which encode 38 and 21 proteins, respectively. Thirty-six of these genes exist in duplicate gene-pairs.A combination of genome analysis, phylogenetic analysis and mRNA expression analysis were employed to examine the conservation of structure, function and evolution of fla1 and fla2 in R. sphaeroides. The results demonstrated that fla2, which was shared among members of ?-Proteobacteria, is native toR. sphaeroides, while fla1 was horizontally transferred from a member of ?-Proteobacteria.In addition, genes located in fla1 are expressed over several growth conditions, but those in fla2 are barely expressed.展开更多
文摘Flagella,the basic locomotive organ in algae,as well as bacteria and some cells of animals or high plants,would be damaged in the well stirred mass culture due to the strong forces caused by the fast mixing impellers. The dynamic regeneration of the flagella in deflagellated Dunaliella salina was studied microscopically by using a bench top flat bottom photobioreactor. The results showed that 90 minutes was necessary for the repair of flagella,after which half of the cells became motile as their flagella generated within 120 minutes and nearly all of the cells could swim freely within 180 minutes.
文摘Nanomachines are controllable machines at the nano meter or molecular scale that are composed of nano-scale components.They have their own mechanochemistry,dynamics,workspace,and usability and are composed of nature's building blocks:namely proteins,DNA,and other compounds.Some bacteria(i.e.Escherichia coli)swim by rotating helical flagella.The structure and motion character of the flagellum are introduced.Through the study,a micro-robot was designed and its mechanical structure was explained in this paper.In the future,the bionic micro-robot is expected tobe built,which can travel inside the human body and carry out a host of complex operations such as minimally invasive surgery,highly localized drug delivery,and screening for diseases that are in their very early stages.It is important to medicine and could be applied in other areas,including space exploration,electronics and military.
文摘MUC1, a tumor-associated antigen overexpressed in many carcinomas, represents a candidate of choice for cancer immunotherapy. Flagella-based MUC1 vaccines were tested in therapeutic setting in two aggressive breast cancer models, comprising the implantation of the 4T1-MUC1 cell line in either Balb/c, or Human MUC1 transgenic mice in which spontaneous metastases occurs. Recombinant flagella carrying only 7 amino acid of MUC1 elicited therapeutic activity, affecting both the growth of established growing tumors and the number of metastases. Higher therapeutic activity was achieved with an additional recombinant flagella designed with the SYFPEITHI algorithm. The vaccines triggered a Th1 response against MUC1 with no evident autoimmune response towards healthy MUC1-expressing tissues. Recombinant flagella carrying a 25-residue fragment of MUC1, induced the most effective response, as evidenced by a significant reduction of both the size and growth rate of the tumor as well as by the lower number of metastases, and expanding life span of vaccinated mice.
文摘Cilia and flagella are organelles of motility that enable cells to swim or move liquid over its surface. An exhaustive literature survey for the presence of the organelle in organisms across phyla showed that most animal cells harbor cilia in contrast to very few fungal cells. While this was not unexpected, it was the position and arrangement of this organelle in each cell that intrigued our attention. Natural selection might have favored motility over chemotaxis;and it would have done so to evolve a stable structure that could have undergone an optimization process requiring a precise geometry in the shape of cells and the structure that would help cells to move. The positioning of such a structure would play a pre-dominant role in optimal motility. It is now known that the flagellar position of a cell is a genetically distinct trait, occasionally used in phylogeny of bacteria, distributed in distinguishing patterns over cellular surface, but basically are of two types, either polar (one flagellum arising from one pole per cell) or peritrichous (lateral flagella distributed over the entire cell surface). Irrespective of the cellular habitat, flagella origin, ultrastructure and proteome, the present investigation surveyed 26 sub-types of flagellar arrangements from as many species as possible. A peculiar pattern ensued-Prokaryotes harbored predominantly polar and peritrichous types;eukaryotes showed a mere change of the peritrichous one. These numbers when used to create a Similarity tree depicted a similarity distance of 14 between the Eubacteria and Archaebacteria forming the first neighborhood;Protozoans, Algae, Fungi, Plantae and Animalia formed a second neighborhood. We offer a working hypothesis for this pattern and the gradual shift in the flagellar arrangement from polar, peritrichous, sub-apical, and apical to lateral throughout evolution.
文摘Rhodobacter sphaeroides 2.4.1 belongs to the?-3 subdivision of the Proteobacteria. It possesses a multipartite genome structure consisting of two circular chromosomes, andit displays a wide range of metabolic diversity.Approximately 40 flagellar proteins are required for structure, assembly, and regulation of the flagellum formation in most bacterial species. R. sphaeroidescontains two flagellar gene clusters (fla1 and fla2),which encode 38 and 21 proteins, respectively. Thirty-six of these genes exist in duplicate gene-pairs.A combination of genome analysis, phylogenetic analysis and mRNA expression analysis were employed to examine the conservation of structure, function and evolution of fla1 and fla2 in R. sphaeroides. The results demonstrated that fla2, which was shared among members of ?-Proteobacteria, is native toR. sphaeroides, while fla1 was horizontally transferred from a member of ?-Proteobacteria.In addition, genes located in fla1 are expressed over several growth conditions, but those in fla2 are barely expressed.
