Three motAB Stator Gene Products in Bdellovibrio bacteriovorus Contribute to Motility of a Single Flagellum during Predatory and Prey-Independent Growth

ABSTRACT The availability of the complete genome sequence of Bdellovibrio bacteriovorus provides an opportunity for investigating genes that play a significant role in predation. Using two independently derived facultatively predatory Bdellovibrio strains, we have designed a method to cultivate and screen transposon insertion mutants in 96-well microtiter dishes. Transposon insertion mutants were produced by introducing the plasposon pRL27, which carries a mini-Tn5. Mutants have been screened for predatory activity using 96-well plates. Seventeen independent nonpredatory mutants have been isolated, and DNA flanking the insertion has been sequenced. BLAST analysis revealed that most of these interrupted DNA sequences do not code for known proteins or functions. Two of the inactivated genes were analyzed further: one was found to code for a putative serine protease and the other a probable protein involved in secretion through the outer membrane. The methods described here are the first for the generation and isolation of predation-deficient mutants using random-transposon-insertion mutagenesis. As more mutants are isolated and their gene products analyzed, more light will be shed on how this predator carries out its exclusive life processes and perhaps how these products, or the organism itself, can be used for therapeutic, agricultural, and/or other purposes.

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Identification of a baculovirus polyhedron formation mutant with a novel phenotype

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166440 ◽

1996 ◽

Vol 54 ◽

pp. 796-797

Author(s):

James M. Slavicek ◽

Melissa J. Mercer ◽

Mary Ellen Kelly

Keyword(s):

Viral Gene ◽

Gene Products ◽

Type Number ◽

Infection Cycle ◽

Wild Type ◽

Protein Matrix ◽

Insect Midgut ◽

Viral Particles ◽

Budded Virus ◽

Viral Form

Nucleopolyhedroviruses (NPV, family Baculoviridae) produce two morphological forms, a budded virus form and a viral form that is occluded into a paracrystalline protein matrix. This structure is termed a polyhedron and is composed primarily of the protein polyhedrin. Insects are infected by NPVs after ingestion of the polyhedron and release of the occluded virions through dissolution of the polyhedron in the alkaline environment of the insect midgut. Early after infection the budded virus form is produced. It buds through the plasma membrane and then infects other cells. Later in the infection cycle the occluded form of the virus is generated (reviewed by Blissard and Rohrmann, 1990).The processes of polyhedron formation and virion occlusion are likely to involve a number of viral gene products. However, only two genes, the polyhedrin gene and 25K FP gene, have been identified to date that are necessary for the wild type number of polyhedra to be formed and viral particles occluded.

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New insights into heparan sulphate biosynthesis from the study of mutant mice

Biochemical Society Symposium ◽

10.1042/bss0690047 ◽

2002 ◽

Vol 69 ◽

pp. 47-57 ◽

Cited By ~ 8

Author(s):

Catherine L. R. Merry ◽

John T. Gallagher

Keyword(s):

Growth Factors ◽

Biosynthetic Pathway ◽

Heparan Sulphate ◽

Mutant Mice ◽

Gene Products ◽

Multiple Gene ◽

Adhesion Proteins ◽

Ligand Interactions

Heparan sulphate (HS) is an essential co-receptor for a number of growth factors, morphogens and adhesion proteins. The biosynthetic modifications involved in the generation of a mature HS chain may determine the strength and outcome of HS–ligand interactions. These modifications are catalysed by a complex family of enzymes, some of which occur as multiple gene products. Various mutant mice have now been generated, which lack the function of isolated components of the HS biosynthetic pathway. In this discussion, we outline the key findings of these studies, and use them to put into context our own work concerning the structure of the HS generated by the Hs2st-/- mice.

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