Biomedical subjects

C F Reichelderfer

Publications and source records attributed to C F Reichelderfer.

11 recordsLinked to original sources

PubMed1989

Another version of the human insulin receptor kinase domain: expression, purification, and characterization.

We have overexpressed another insulin receptor kinase molecule, which consists of residues 941-1343 inclusive of the human insulin receptor, by using the baculo-virus expression vector pVL941. Unlike the two previous preparations of insulin receptor kinase in this expression system, this molecule contains the complete unmodified sequence of the cytoplasmic domain of the human insulin receptor beta subunit. Our construct allows high-level expression of the recombinant protein in cultured Sf9 cells and in cabbage looper (Trichoplusia ni) larvae. An improved purification procedure yields greater than or equal to 95% pure protein in 55% yield from the cells. The specific activity of this purified protein is 3.5-fold greater than from the previously described baculovirus insulin receptor kinase (that included residues 946-1343 from the proreceptor). Like the latter molecule, the insulin receptor kinase molecule reported here sediments as a monomer, and its autophosphorylation occurs by an intramolecular process. Preliminary data about the spectroscopic features of the cytosolic domain of the human insulin receptor are presented.

Animals↗

PubMed1989

Complementation of recombinant baculoviruses by coinfection with wild-type virus facilitates production in insect larvae of antigenic proteins of hepatitis B virus and influenza virus.

We describe the coinfection of insects with wild-type and recombinant baculoviruses in which the polyhedrin gene promoter is used to express hepatitis B virus envelope protein (hepatitis B virus surface antigen; HBsAg) or influenza A virus neuraminidase (NA). Viruses were administered per os to larvae of the cabbage looper, Trichoplusia ni, causing an infection that within 5 days resulted in the production of approximately 0.15 mg of HBsAg per insect, representing 1.5% of the total extracted protein, or approximately 2.8 mg of NA per insect, representing 28% of the total extractable protein. The HBsAg and NA produced by infected larvae were purified from insect lysates. These proteins were antigenic as determined by conformation-dependent immunoassays. The NA was enzymatically active with conventional substrates. The method of infection described allows genetic complementation by wild-type virus of recombinant viruses lacking the polyhedrin gene essential for infection per os and has implications for the high-yield production in insect larvae of other recombinant proteins of baculoviruses.

Animals↗

PubMed1987

Selective Process for Efficient Isolation of Soil Bacillus spp.

We were able to isolate Bacillus thuringiensis from environmental samples with a background of 10 bacteria per g of soil. Our selection process differed significantly from classical selection methods which permit only the desired organism to grow. In our process, germination of B. thuringiensis spores was selectively inhibited by sodium acetate, while most of the undesired sporeformers germinated. Next, all of the nonsporulated microbes were eliminated by heat treatment at 80 degrees C for 3 min. The surviving spores were then plated on a rich agar medium and allowed to grow until they sporulated. Of random colonies picked from agar, 20 to 96% were crystal-forming Bacillus species. B. thuringiensis and B. sphaericus were routinely selected by this method.

Journal Article↗

PubMed1982

Rifampin inhibition of the occluded virus form of a nuclear polyhedrosis virus.

Rifampin at concentrations toxic to noninfected cells but not to infected cells is a selective inhibitor of occluded virus of the group A Baculoviridae (nuclear polyhedrosis virus). However, the titer of nonoccluded virus is not affected. Rifampin blocks occlusion until late in the replication cycle (14 to 16 h), and its effects are reversible. Modes of action of polyhedral inclusion body production are unknown.

Inclusion Bodies↗

PubMed1981

Physical Factors That Affect In Vitro Autographa californica Nuclear Polyhedrosis Virus Infection.

Of the physical parameters tested for in vitro baculovirus infection, multiplicity of infection was most important in governing percent cell infection. Most plaques formed within the first 5 min of incubation. Efficiency of infection, however, was low, and the virus titer did not diminish during prolonged incubation. Efficiency of infection improved markedly when cells or virus were preincubated with selected polyanions and polycations. Precise regulation of the pH, osmotic pressure, and ionic composition of the cell culture medium also promoted maximum in vivo infection.

Journal Article↗

PubMed1975

Characteristics of the non-occluded form of a nuclear polyhedrosis virus.

Non-occluded virions of a nuclear polyhedrosis virus of the alfalfa looper, Autographa californica, found in the medium of cell cultures of infected fall armyworm, Spodopter frugiperda, and in the hemolymph of infected S. frugiperda larvae were partially characterized by biological, chemical and physical methods. Also, the rate of appearance of the virions was studied in cell culture and the host insect to determine maximum virion production. Virions obtained from both sources were heat-sensitive, acid-labile and inactivated by several organic solvents. The non-occluded virions found in the insect cell culture fluid and in the hemolymph were identical, and both were enveloped nucleocapsids. Visualization of the fragilely enveloped nucleocapsid was accomplished only after fixation with glutaraldehyde. Differences between the non-occluded and occluded virions of nuclear polyhedrosis viruses are discussed.

Acids↗

PubMed1974