john lagnado | Royal Holloway, University of London (original) (raw)
Papers by john lagnado
It was within the relatively modest facilities at the Endell Street laboratories that Fred Griffi... more It was within the relatively modest facilities at the Endell Street laboratories that Fred Griffith carried out the extensive research on the typing of bacteria that led him to discover the remarkable phenomenon of transformation of pneumococcal types, which, at the time,
Biochemical Society Transactions, 1976
Advances in biochemical psychopharmacology
Biochemical Society Transactions, 1983
Neurochemical Research, 1996
ABSTRACT Microtubules were prepared by temperature-dependent cycles of assembly/disassembly from ... more ABSTRACT Microtubules were prepared by temperature-dependent cycles of assembly/disassembly from chick brain labeled in vivo with 32Pi and the distribution of labeled phospholipids extracted from cold-insoluble and soluble microtubular protein fractions was analyzed by thin-layer and paper chromatography. While 32P-labeling was associated with all of the phospholipids identified after 2-D TLC, it was found that all of the relatively high radioactivity associated with phosphatidylserine (PS) was in fact associated with a minor co-migrating component which was subsequently identified as phosphatidylinositol(PI) by three independent separation procedures. It was estimated that the relative specific radioactivity in PI was several-fold higher than that associated with other microtubule-associated phospholipids. Additional experiments, in which the protein components of once-cycled microtubules were fractionated by gel permeation chromatography, provided evidence that the 36S component containing ring-like tubulin oligomers (36S) appears to be selectively associated with phospholipid components that were specifically enriched in 32P-PI. The possible significance of these findings is discussed in relation to the effects of phospholipids on microtubule dynamics and to the function of microtubules in their interactions with membranes.
Biochemical Society transactions, 1975
Biochemical Society transactions, 1976
... AHMED N. ITANI and JOHN R. LAGNADO ... the Vincu alkaloids, vinblastine and vincristine, are ... more ... AHMED N. ITANI and JOHN R. LAGNADO ... the Vincu alkaloids, vinblastine and vincristine, are commonly used as probes for microtubule-dependent processes in various cell types (see, for example, Oliver et al., 1974; Edelman et al., 1974; Nicolson, 1976; McClure, 1972): both ...
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1958
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1956
Journal of Neurochemistry, 1976
The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guine... more The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guinea-pig cerebral cortex labelled with [32P]orthophosphate was investigated. Under the conditions tested, both and the α and β forms of tubulin contained metabolically-active P which accounted for about one third of the total 32P incorporated into protein; the remaining protein-bound 32P was associated with 3–4 minor high MW components co-purifying with tubulin during two cycles of assembly4sassembly. Microtubular protein prepared in this way contained approx. 0.8 mol of alkali-labile P/mol of tubulin dimer (M.W. 110,000).In vitro studies showed that reassembled microtubular protein preparations catalysed the incorporation of up to 0.55 mol of P/mol of tubulin dimer during incubation with Mg2+ and [γ32P]ATP. The reaction was linear during the first 30 min of incubation at 37°C. Cyclic AMP (10 μm, final concentration) caused a transient increase in the initial rates of tubulin phosphorylation. Little label was incorporated into the minor high M.W. components under these conditions. The in vitro phosphorylation of microtubular protein increased in a non-linear manner with respect to protein concentration: this was in contrast to earlier experiments showing linear kinetics when chromatographically isolated tubulin was tested for intrinsic kinase activity. Isolated microtubular protein preparations bound [3H]GTP, [3H]ATP and to a lesser extent, [3H]cyclic AMP, and exhibited Ca2+-ATPase activity (up to 60pmol Pi released min/mg protein at 37°C).
Parasitology Research, 2000
Phytomonas sp. derived from Euphorbia pinea are digenetic plant trypanosomes that are transmitted... more Phytomonas sp. derived from Euphorbia pinea are digenetic plant trypanosomes that are transmitted by the squashbug Stenocephalus agilis and exist exclusively as promastigotes. The stable sub-pellicular microtubular array, the flagellar axoneme and the paraflagellar rod represent the major cytoskeletal components common to all trypanosomes. The work described in this paper examines in detail the ultrastructural morphology of the organism and highlights a number of novel structural features, and in particular, the presence of some detergent-resistant proteins which take the form of bundles of trans-cytoplasmic filaments of ca. 10 nm in diameter, seen in cells from both log- and stationary-phase cultures. The ultrastructural morphology and immunological cross-reactivity of these filaments are described, and their relationship to filamentous bundles previously reported in stationary-phase cultures of Crithidia fasciculata and to intermediate filaments of animal cells is discussed.
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1956
It was within the relatively modest facilities at the Endell Street laboratories that Fred Griffi... more It was within the relatively modest facilities at the Endell Street laboratories that Fred Griffith carried out the extensive research on the typing of bacteria that led him to discover the remarkable phenomenon of transformation of pneumococcal types, which, at the time,
Biochemical Society Transactions, 1976
Advances in biochemical psychopharmacology
Biochemical Society Transactions, 1983
Neurochemical Research, 1996
ABSTRACT Microtubules were prepared by temperature-dependent cycles of assembly/disassembly from ... more ABSTRACT Microtubules were prepared by temperature-dependent cycles of assembly/disassembly from chick brain labeled in vivo with 32Pi and the distribution of labeled phospholipids extracted from cold-insoluble and soluble microtubular protein fractions was analyzed by thin-layer and paper chromatography. While 32P-labeling was associated with all of the phospholipids identified after 2-D TLC, it was found that all of the relatively high radioactivity associated with phosphatidylserine (PS) was in fact associated with a minor co-migrating component which was subsequently identified as phosphatidylinositol(PI) by three independent separation procedures. It was estimated that the relative specific radioactivity in PI was several-fold higher than that associated with other microtubule-associated phospholipids. Additional experiments, in which the protein components of once-cycled microtubules were fractionated by gel permeation chromatography, provided evidence that the 36S component containing ring-like tubulin oligomers (36S) appears to be selectively associated with phospholipid components that were specifically enriched in 32P-PI. The possible significance of these findings is discussed in relation to the effects of phospholipids on microtubule dynamics and to the function of microtubules in their interactions with membranes.
Biochemical Society transactions, 1975
Biochemical Society transactions, 1976
... AHMED N. ITANI and JOHN R. LAGNADO ... the Vincu alkaloids, vinblastine and vincristine, are ... more ... AHMED N. ITANI and JOHN R. LAGNADO ... the Vincu alkaloids, vinblastine and vincristine, are commonly used as probes for microtubule-dependent processes in various cell types (see, for example, Oliver et al., 1974; Edelman et al., 1974; Nicolson, 1976; McClure, 1972): both ...
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1958
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1956
Journal of Neurochemistry, 1976
The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guine... more The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guinea-pig cerebral cortex labelled with [32P]orthophosphate was investigated. Under the conditions tested, both and the α and β forms of tubulin contained metabolically-active P which accounted for about one third of the total 32P incorporated into protein; the remaining protein-bound 32P was associated with 3–4 minor high MW components co-purifying with tubulin during two cycles of assembly4sassembly. Microtubular protein prepared in this way contained approx. 0.8 mol of alkali-labile P/mol of tubulin dimer (M.W. 110,000).In vitro studies showed that reassembled microtubular protein preparations catalysed the incorporation of up to 0.55 mol of P/mol of tubulin dimer during incubation with Mg2+ and [γ32P]ATP. The reaction was linear during the first 30 min of incubation at 37°C. Cyclic AMP (10 μm, final concentration) caused a transient increase in the initial rates of tubulin phosphorylation. Little label was incorporated into the minor high M.W. components under these conditions. The in vitro phosphorylation of microtubular protein increased in a non-linear manner with respect to protein concentration: this was in contrast to earlier experiments showing linear kinetics when chromatographically isolated tubulin was tested for intrinsic kinase activity. Isolated microtubular protein preparations bound [3H]GTP, [3H]ATP and to a lesser extent, [3H]cyclic AMP, and exhibited Ca2+-ATPase activity (up to 60pmol Pi released min/mg protein at 37°C).
Parasitology Research, 2000
Phytomonas sp. derived from Euphorbia pinea are digenetic plant trypanosomes that are transmitted... more Phytomonas sp. derived from Euphorbia pinea are digenetic plant trypanosomes that are transmitted by the squashbug Stenocephalus agilis and exist exclusively as promastigotes. The stable sub-pellicular microtubular array, the flagellar axoneme and the paraflagellar rod represent the major cytoskeletal components common to all trypanosomes. The work described in this paper examines in detail the ultrastructural morphology of the organism and highlights a number of novel structural features, and in particular, the presence of some detergent-resistant proteins which take the form of bundles of trans-cytoplasmic filaments of ca. 10 nm in diameter, seen in cells from both log- and stationary-phase cultures. The ultrastructural morphology and immunological cross-reactivity of these filaments are described, and their relationship to filamentous bundles previously reported in stationary-phase cultures of Crithidia fasciculata and to intermediate filaments of animal cells is discussed.
Biochemistry and Cell Biology-biochimie Et Biologie Cellulaire, 1956