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Biomedical subjects

D Hodgson

Publications and source records attributed to D Hodgson.

33 records · Page 2Linked to original sources
PubMed1993

Production of recombinant notechis 11'2L, an enzymatically active mutant of a phospholipase A2 from Notechis scutatus scutatus venom, as directly generated by cleavage of a fusion protein produced in Escherichia coli.

We have constructed an expression vector to produce, in Escherichia coli, a fusion protein containing successively two IgG binding domains from staphyloccocal protein A, a nine-amino-acid linker peptide terminating in a methionine residue and the phospholipase A2 notechis 11'2L, an isoform of notexin of Notechis scutatus scutatus venom. Notechis 11'2L is a mutant of the naturally occurring notechis 11'2 [Bouchier, C., Boyot, P., Tesson, F., Trémeau, O., Bouet, F., Hodgson, D., Boulain, J. C. & Ménez, A. (1991) Eur. J. Biochem. 202, 493-500] in which Met8 has been replaced by Leu. The fusion protein was recovered in the periplasmic extract with a yield of 0.25 mg/l culture. It was hydrolyzed with cyanogen bromide, yielding a protein having the molecular mass, amino acid composition and N-terminal sequence of notechis 11'2L. Notechis 11'2L and the wild notechis 11'2 displayed identical circular dichroic spectra and shared similar enzymatic, myotoxic and antigenic properties, suggesting that the recombinant notechis 11'2L was directly generated in a correctly folded form.

Base Sequence↗
PubMed1991

Notechis 11'2, a non-toxic phospholipase A2 from the venom of Notechis scutatus scutatus.

Previously, we deduced the amino acid sequence of a novel phospholipase-A2-like protein (PLA2) from the nucleotide sequence of a cDNA isolated from a library prepared from the venom gland of the Australian elapid Notechis scutatus scutatus. The corresponding protein has now been identified, purified from the venom and named Notechis 11'2. Its complete amino acid sequence has been determined by automated Edman degradation of both the whole protein and peptides generated by Staphylococcus aureus protease digestion and chemical cleavage at a tryptophan residue. As predicted from its sequence which contains all the residues putatively required for PLA2 activity, Notechis 11'2 exhibits an esterase activity, preferentially against neutral phospholipids. However, despite its sequence homology with other highly toxic PLA2 present in the venom of Notechis scutatus scutatus, notechis 11'2 has no lethal activity. This observation further supports the view that the lethal activity of PLA2 from Notechis scutatus scutatus is not due to the esterasic activity only.

Amino Acid Sequence↗
PubMed1991

Clinical investigations of halothane and isoflurane for induction and maintenance of foal anesthesia.

Fifty-eight foals were divided into two groups for study of aspects of the clinical anesthetic management of foals and to characterize effects of halothane (n = 30) and isoflurane (n = 28) in foals. There were no significant differences (P greater than 0.05) in the demographics of the two groups. Results of hemograms and biochemical analysis of venous blood samples before and after anesthesia were either not influenced or only mildly (clinically unimportant) affected by either agent. Like adult horses, foals have an increased PaCO2 when anesthetized with inhaled anesthetics. We could detect no difference in the magnitude of increase in PaCO2 with either anesthetic. Anesthetic induction and recovery was most rapid with isoflurane. The quality of induction and recovery was similarly acceptable with either agent. Heart rate during isoflurane was not significantly different from conscious conditions but during halothane, heart rate was significantly less than control except at 91-120 min when statistical significance was not detected. These results support the clinical impression that foals can be safely and reliably anesthetized with either agent.

Anesthesia, Inhalation↗
PubMed1987

Influence of husbands on the outcome of their agoraphobic wives' therapy.

Of 30 agoraphobic married women undertaking home-based behaviour therapy, 15 each had a female friend as co-therapist and 15 had their own husband as co-therapist. At 12 months follow-up, women spent a mean of approximately 40 minutes a day more outside the home alone than at baseline. Women assisted by female friends made somewhat more behavioural gains than those assisted by husbands. Women in both groups whose husbands had been more depressed 2 months after the beginning of therapy did less well at 6 months. Husbands who become more depressed may retard their wives' progress in therapy, but the effect was small, and was outweighed by other considerations.

Adolescent↗
PubMed1985

Phosphorylation of the beta' Subunit of RNA Polymerase and Other Host Proteins upon phiCd1 Infection of Caulobacter crescentus.

A protein kinase activity is induced early after infection of Caulobacter crescentus by the DNA phage phiCd1. After phage infection at least 40 proteins are phosphorylated; these include DNA-binding proteins, a membrane-associated protein, and several ribosomal proteins. One of the phosphorylated DNA-binding proteins was identified as the beta' subunit of the host RNA polymerase.

Journal Article↗
PubMed1984

Caulobacter crescentus fatty acid-dependent cell cycle mutant.

A fatty acid auxotroph of Caulobacter crescentus, AE6001, which displays a strict requirement for unsaturated fatty acids to grow on glucose as the carbon source has been isolated. Starvation of AE6001 for unsaturated fatty acids resulted in a block in the cell cycle. Starved cultures accumulated at the predivisional cell stage after a round of DNA replication had been completed and after a flagellum had been assembled at the pole of the cell. Cell division and cell growth failed to occur probably because the mutant was unable to synthesize a membrane. An analysis of double mutants containing the fatB503 allele and other mutations in membrane biogenesis demonstrated that the cell cycle of AE6001 blocked at a homeostatic state. The addition of oleic acid to starved cultures permitted cell division and the initiation of a new round of DNA replication. The coincident block in both the initiation of DNA replication and membrane assembly, exhibited by starved cultures of this mutant, suggests that the fatB503 gene product may be involved in the coordination of these events.

Bacteria↗
PubMed1984

Genetic analysis and characterization of a Caulobacter crescentus mutant defective in membrane biogenesis.

A mutant of Caulobacter crescentus has been isolated which has an auxotrophic requirement for unsaturated fatty acids or biotin for growth on medium containing glucose as the carbon source. This mutant exhibits a pleiotropic phenotype which includes (i) the auxotrophic requirement, (ii) cell death in cultures attempting to grow on glucose in the absence of fatty acids or biotin, and (iii) a major change in the outer membrane protein composition before cell death. This genetic lesion did not appear to affect directly a fatty acid biosynthetic reaction because fatty acid and phospholipid syntheses were found to continue in the absence of supplement. Oleic acid repressed fatty acid biosynthesis and induced fatty acid degradation in the wild-type parent, AE5000 . The mutant strain, AE6000 , was altered in both of these regulatory functions. The AE6000 mutant also showed specific inhibition of the synthesis of outer membrane and flagellar proteins. Total phospholipid, DNA, RNA, and protein syntheses were unaffected. The multiple phenotypes of the AE6000 mutant were found to cosegregate and to map between hclA and lacA on the C. crescentus chromosome. The defect in this mutant appears to be associated with a regulatory function in membrane biogenesis and provides evidence for a direct coordination of membrane protein synthesis and lipid metabolism in C. crescentus.

Bacteria↗
PubMed1983

Malignant hyperthermia-like reactions in three anesthetized horses.

Problems encountered during halothane anesthesia in 3 horses included increasing rectal temperature, muscle rigidity or movement during anesthesia, irregular breathing patterns, and difficulty in stabilizing blood pressure. One horse had prolonged muscle fasciculations and failure to relax after administration of succinylcholine in addition to halothane. That horse developed severe, bilateral myositis of the triceps, lumbar, and gluteal muscles. Problems encountered were similar to those caused by the disease known as malignant hyperthermia.

Anesthesia, General↗
PubMed1979

Electrocardiography, heart scope and haematology of horses competing in an endurance ride.

Thirty-one horses competing in a 100 kilometre endurance ride had electrocardiograms recorded before and after the ride from which the heart score of each horse was calculated. Blood was also taken to determine the packed cell volume (PCV) and total plasma protein (TPP) before the ride, after 60 kilometres (mid ride) and at completion of the ride. Statistical analysis of the heart scores showed that a faster group of horses had significantly higher heart scores than either a slower group or those eliminated due to inadequate recovery of heart rate. No horses developed electrocardiogram abnormalities as a result of the ride. Analysis of the results of PCV and TPP showed that horses became dehydrated during the ride. The faster group of horses had significantly higher PCV values and heart rates at both the mid-ride and end of ride sampling times. However, the TPP values indicated no significant differences in the amount of dehydration between the 2 groups.

Animals↗