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V Brenner

Publications and source records attributed to V Brenner.

23 records · Page 2Linked to original sources
PubMed1987

Mini-Mu transposition of bacterial genes on the transmissible plasmid.

Using the pRM30 plasmid, an Aps deletion derivative of broad host range plasmid RP4 with integrated new miniMu 5 (11 kb), we followed the transfer of Escherichia coli chromosomal genes to the recipient strain. The miniMu 5-mediated transposition of chromosomal genes occurs onto the plasmid with integrated miniMu 5 rather than onto the "recipient" plasmid pNH602. The plasmid DNA in recipient cells was detected by electrophoresis. One of the acquired hybrid plasmids pTB2 was analyzed genetically and by restriction endodeoxyribonuclease digestion. A structure consisting of miniMu-chromosomal segment-miniMu as a product of Mu-mediated transposition was detected.

Chromosome Deletion↗
PubMed1986

Ion fluxes changes during early stages of Schistosoma mansoni. Evaluation of complement effect.

The relationship between the average membrane potential (delta psi av) and sensitivity to complement action of the Schistosoma mansoni parasite was explored. The average membrane potential was estimated by measuring the uptake of [3H]tetraphenyl phosphonium ([3H]Ph4P+). The parasites take up Ph4P+ indicating the existence of a negative internal plasma potential which is in part dependent on the transmembrane K+ gradient, maintained by an active Na+/K+-ATPase. Values for Ph4P+ uptake could be corrected for mitochondrial accumulation by employing the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP), which collapses the mitochondrial potential. The plasma membrane potential derived by this technique was in the range of -60 mV. Transformation of this parasite, from its early cercaria stage to the adult worm, was associated with changes in the average membrane potential. The apparent hyperpolarization, which accompanies transformation, may be related to changes in ionic permeability and morphology which occur concomitantly. Complement acting through both the classical and alternative pathways was found to affect the potential of the parasite in its early development stages. The correlation between effects on delta psi av and sensitivity to complement action, indicates that the complement-induced changes in delta psi av are indeed tightly associated with its mode of action. Treatment of the parasite with complement resulted in net hyperpolarization of the membrane indicating that hyperpolarization rather than depolarization of the membrane is linked to the primary non-lethal action of complement.

Animals↗
PubMed1985

In vivo protection against S. mansoni infection by monoclonal antibodies.

A monoclonal antibody of the IgG1 class (27.21), that was previously shown to be cytotoxic in vitro to the schistosomula, conferred partial protection in vivo against challenge infection with S. mansoni. Monoclonal antibodies of the IgE class (54.10) were not effective in these experiments, but were capable of causing specific degranulation of basophilic cells upon contact with the young larva (3-6 h). The relevance of the IgE antibodies to protection observed in immunized mice is discussed.

Animals↗
PubMed1985

Protective monoclonal antibody against Schistosoma mansoni: antigen isolation, characterization, and suitability for active immunization.

Monoclonal antibodies that bind to the surface of developing schistosomula were generated from the spleens of chronically infected mice that were boosted with cercarial glycoproteins. The two most reactive monoclonal antibodies, denoted 152-66-9B and 152-66-1C, were used for identification of surface antigens. The antigen detected by these monoclonal antibodies persisted on the surface of the developing larva for 72 hr posttransformation. This monoclonal antibody effected complement-mediated killing of schistosomula in vitro as efficiently as infected mouse sera. It was also very efficient in inhibiting the infectivity of both cercariae and schistosomula. The antigen reactive with the 152-66-9B monoclonal antibody contains two major polypeptides (45 and 30 KD). These polypeptide chains might have originated from the same protein, because they have the same isoelectric point in two-dimensional gel electrophoresis. Moreover, the affinity-purified antigen migrated as only one protein band of approximately 200 KD in SDS-PAGE in nonreducing conditions. The 9B antigen was isolated, purified, and used for immunization, resulting in an antigen dose-dependent partial protection against S. mansoni infection.

Animals↗