scholarly journals Isolation of material displaying insulin-like immunological biological activity from the brain of the blowfly Calliphora vomitoria

1979 ◽  
Vol 184 (2) ◽  
pp. 221-227 ◽  
Author(s):  
H Duve ◽  
A Thorpe ◽  
N R Lazarus
Keyword(s):  
Biological Activity ◽  
Neurosecretory Cell ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Insulin Receptors ◽  
Neurosecretory Cells ◽  
Bovine Insulin ◽  
Fat Cell ◽  
Median Neurosecretory Cells ◽  
The Brain

An insulin-like material from the brain of the blowfly Calliphora vomitoria was partially purified by acid alcohol extraction, gel filtration and ion-exchange cellulose chromatography. In addition, the RF value on polyacrylamide-gel electrophoresis was determined. The material was characterized by its ability to cross-react with bovine insulin antibody and by displaying diminished immunoreactivity on dilution. It displaced specifically bound 125I-labelled insulin from rat liver plasma membrane insulin receptors and displayed insulin-like biological activity on the isolated rat fat-cell. Within 30 min of injection into Calliphora, made hypertrehalocaemic and hyperglucaemic as a result of median neurosecretory cell removal, it caused the concentrations of both sugars to return to normal. The hypothesis is put forward that the median neurosecretory cells are the source of the material.

scholarly journals 4-pyridylmethyl, a thiol-protecting group suitable for the partial synthesis of proteins

1979 ◽  
Vol 179 (1) ◽  
pp. 119-126 ◽  
Author(s):  
U T Rüegg ◽  
D Jarvis ◽  
J Rudinger
Keyword(s):  
Biological Activity ◽  
Acid Hydrolysis ◽  
Gel Filtration ◽  
Bovine Insulin ◽  
Protecting Group ◽  
Dilute Acid ◽  
Total Acid ◽  
Partial Synthesis ◽  
Medium Ph ◽  
Good Solubility

Cysteine is converted into S-4-pyridylmethylcysteine [Gosden, Stevenson & Young (1972) J. Chem. Soc. Chem Commun. 1123-1124] by 4-pyridylmethyl chloride in aqueous propanol at pH 8.3. The derivative is stable to the conditions of total acid hydrolysis. Reduction and alkylation of bovine insulin (pH 8.3, aq. 50% propanol) gives fully S-substituted derivatives in excellent yields. The S-pyridylmethylated A- and B-chains of insulin were separated by gel filtration: each of them has good solubility properties. The pyridylmethyl group is cleaved by electrolysis in a dilute acid medium, pH 2.6, to give reduced chains. They can be recombined to give insulin in the same yield and with the same degree of biological activity as chains which had not been subjected to the protection and de-protection steps. The results indicate that pyridylmethyl satisfactorily meets requirements for partial synthesis and suggest that it warrants more general use.

Ovulation in Rhodnius prolixus Stal is induced by an extract of neurosecretory cells

1983 ◽  
Vol 61 (3) ◽  
pp. 684-686 ◽  
Author(s):  
F. L. Kriger ◽  
K. G. Davey
Keyword(s):  
Neurosecretory Cells ◽  
Rhodnius Prolixus ◽  
Pars Intercerebralis ◽  
Median Neurosecretory Cells ◽  
The Brain

The injection of an extract of 10 identified median neurosecretory cells from the pars intercerebralis into gravid mated females previously deprived of these cells by surgery induces ovulation and oviposition during the ensuring 24 h. Injection of an extract of ocellar nerves has no effect. These observations support the hypothesis that ovulation and oviposition are controlled by a myotropin released from neurosecretory cells in the brain.

scholarly journals Biosynthesis of glucagon in isolated pancreatic islets of guinea pigs

1974 ◽  
Vol 140 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Claes Hellerström ◽  
Simon L. Howell ◽  
John C. Edwards ◽  
Arne Andersson ◽  
Claes-Göran Östenson
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Gel Filtration ◽  
Subcellular Fractionation ◽  
Fat Cell ◽  
Electron Microscopic ◽  
Isolated Pancreatic Islets ◽  
Isolated Islets Of Langerhans ◽  
Electron Microscopic Radioautography ◽  
Very High

1. The biosynthesis of glucagon in guinea-pig A2 cells was investigated by incubation of isolated islets of Langerhans in the presence of [3H]tryptophan for periods of up to 14 days. Proteins were extracted from islets and incubation media and analysed by gel filtration. 2. In addition to very-high-molecular-weight (100000) proteins, the principal tryptophan-containing biosynthetic product after incubation for up to 17h was a protein of minimum mol.wt. 9000, which co-eluted on gel filtration with a peak of glucagon-like immunoreactivity, but was apparently devoid of biological activity in a fat-cell assay. A discrete peak of labelled glucagon was only recovered after incubation for at least 6 days. Losses of glucagon during the extraction and rapid secretion of newly synthesized glucagon into incubation media were excluded as reasons for the lack of recovery of labelled hormone from islets after shorter incubations. 3. The 9000-mol.wt. protein was localized to A2 cells in experiments using B-cell-depleted islets, and to A2-cell granules by subcellular fractionation and electron-microscopic radioautography. Only glucagon was secreted into the incubation medium. 4. Possible relationships between the 9000-mol.wt. protein and glucagon are discussed in the light of postulated mechanisms of glucagon biosynthesis.

Reproductive growth in normal, allatectomized, median-neurosecretory-cell-cauterized, and ovariectomized females of Melanoplus sanguinipes

1976 ◽  
Vol 54 (2) ◽  
pp. 162-171 ◽  
Author(s):  
C. Gillott ◽  
R. H. Elliott
Keyword(s):  
Body Weight ◽  
Fat Body ◽  
Neurosecretory Cell ◽  
Initial Period ◽  
Somatic Growth ◽  
Neurosecretory Cells ◽  
Corpora Allata ◽  
Oocyte Growth ◽  
Median Neurosecretory Cells ◽  
Growth Changes

Changes in the weight of the whole insect, fat body, and ovary during successive gonotrophic cycles have been measured. The effects of ovariectomy, cautery of the median neurosecretory cells (mNSC), or removal of the corpora allata (CA) on the development of the fat body and reproductive system have also been observed.After an initial period of somatic growth, changes in body weight are very largely due to growth of the proximal oocytes and to oviposition. Yolk deposition begins when the oocytes are1.0 mm long and occurs most rapidly during the final stages of their development. Vitellogenesis begins in the penultimate oocytes when the proximal oocytes are 3.0–3.5 mm long. Ovariectomy results in a significant increase in the weight of the fat body. Removal of the CA prevents oocyte development beyond the 1-mm stage and production of secretion in the lateral oviducts. Both effects can be reversed by treating operated insects with juvenile hormone. Cautery of the mNSC, provided it is carried out within 3 h of emergence, also inhibits oocyte growth and delays the appearance of secretion in the lateral oviducts.

scholarly journals Control of ovarian steroidogenesis by insulin-like peptides in the blowfly (Phormia regina)

2004 ◽  
Vol 181 (1) ◽  
pp. 147-156 ◽  
Author(s):  
G Maniere ◽  
I Rondot ◽  
EE Bullesbach ◽  
F Gautron ◽  
E Vanhems ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Mode Of Action ◽  
Maximal Activity ◽  
Neurosecretory Cells ◽  
Bovine Insulin ◽  
Phormia Regina ◽  
Phosphatidylinositol 3 Kinase ◽  
Ovarian Steroidogenesis ◽  
Median Neurosecretory Cells

This study investigated the ability of insulin and of insect insulin-like peptides (ILPs) to stimulate ovarian steroidogenesis in the blowfly Phormia regina. Bovine insulin was active on ovaries isolated in vitro, which showed an age-dependent sensitivity; this peptide progressively stimulated steroidogenesis in ovaries isolated from the third day after adult molt, but not in younger ones, and had maximal activity after the fifth day. This stimulatory effect was observed equally from females reared in the presence or in the absence of males, excluding a regulatory effect of mating. The mode of action of insulin in blowflies did not involve cAMP, but triggered a specific and well-conserved transduction cascade. In particular, a peroxovanadium compound, known to activate specifically the insulin receptor in mammals, also stimulated blowfly ovarian steroidogenesis in vitro. Conversely, chemicals known to inhibit the mammalian insulin receptor or downstream elements of its signaling pathway, such as LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), were able to prevent the steroidogenic action of bovine insulin on fly ovaries. Extracts from the median neurosecretory cells (MNCs) of blowfly brains, which are known to contain endogenous ILPs, stimulated ovarian steroidogenesis very efficiently and were also sensitive to inhibition by LY294002. These experiments indicated the involvement of PI3K in the mode of action of MNC extracts and substantiated that their endogenous ILPs are involved in the regulation of ovarian steroidogenesis. This conclusion was corroborated by the effects of synthetic bombyxin II, an ILP originating from silkworm MNCs, which also stimulated steroidogenesis in isolated blowfly ovaries. Altogether, these data suggest that insulinlike neurohormones from MNCs play a crucial role as steroidogenic gonadotropins in female flies.

scholarly journals Carboxymethylation of methionine residues in bovine pituitary luteinizing hormone and its subunits. Effects on the binding activity with receptor sites and interactions between subunits

1976 ◽  
Vol 159 (1) ◽  
pp. 71-77 ◽  
Author(s):  
K W Cheng
Keyword(s):  
Biological Activity ◽  
Luteinizing Hormone ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Receptor Site ◽  
Iodoacetic Acid ◽  
Cross Reactivity ◽  
Receptor Interaction ◽  
Beta Subunits ◽  
Methionine Residues

The reaction of iodoacetic acid with bovine lutropin (luteinizing hormone) at pH 3.0 was specific for methionine residues; it was slow and reached its equilibrium after 12 h at 37 degrees C. The number of modified methionine residues increased proportionately with the amount of the alkylating reagent in the reaction mixture. In the presence of a 20-fold molar excess of iodoacetic acid with respect to methionine, essentially all methionine residues in both subunits of bovine lutropin were carboxymethylated. Studies of various recombinations of modified and native alpha and beta subunits showed that methionine residues in bovine lutropin were not essential for interactions between subunits. Various recombinants were characterized by polyacrylamide-gel electrophoresis and gel filtration of Sephadex G-100. Immunological cross-reactivity by radioimmunoassay of the recombinants of modified alpha and beta subunits was relatively similar to that of the native subunits. However, the biological activity measured by receptor-site binding of the recombinants of alpha and beta chains with a total of three alkylated methionine residues was less than 5% of the activity of native lutropin. It is noteworthy that recombinants of a modified subunit and a native counterpart subunit regenerated 20-30 % of biological activity. These findings suggested that at least 1-2 methionine residues in each subunit are involved in the hormone-receptor interaction for bovine lutropin.

scholarly journals Importance of geometry of the extracellular matrix in endochondral bone differentiation.

1984 ◽  
Vol 98 (6) ◽  
pp. 2192-2197 ◽  
Author(s):  
T K Sampath ◽  
A H Reddi
Keyword(s):  
Biological Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Bone Matrix ◽  
Gel Filtration ◽  
Fine Powder ◽  
Critical Factor ◽  
Endochondral Bone ◽  
Bone Differentiation ◽  
Diaphyseal Bone ◽  
The Matrix

Subcutaneous implantation of coarse powders (74-420 micron) of demineralized diaphyseal bone matrix resulted in the local differentiation of endochondral bone. However, implantation of matrix with particle size of 44-74 micron (Fine matrix) did not induce bone. We have recently reported that the dissociative extraction of coarse matrix with 4 M guanidine HCl resulted in a complete loss of the ability of matrix to induce endochondral bone; the total loss of biological activity could be restored by reconstitution of extracted soluble components with inactive residue. To determine the possible biochemical potential of fine matrix to induce bone, the matrix was extracted in 4 M guanidine HCl and the extract was reconstituted with biologically inactive 4 M guanidine HCl-treated coarse bone matrix residue. There was a complete restoration of the biological activity by the extract of fine matrix upon reconstitution with extracted coarse matrix. Polyacrylamide gel electrophoresis of the extract of fine matrix revealed similar protein profiles as seen for the extract of coarse matrix. Gel filtration of the 4 M guanidine HCl extract of fine powder on Sepharose CL-6B and the subsequent reconstitution of various column fractions with inactive coarse residue showed that fractions with proteins of 20,000-50,000 mol wt induced new bone formation. These observations demonstrate that although fine bone matrix contains, osteoinductive proteins, matrix geometry (size) is a critical factor in triggering the biochemical cascade of endochondral bone differentiation. Mixing of coarse matrix with Fine results in partial response and it was confined to areas in contact with coarse particles. The results imply a role for geometry of extracellular bone matrix in anchorage-dependent proliferation and differentiation of cells.

The brain structure and neurosecretory cells of noctuid moth Anadevidia peponis: Noctuidae

1990 ◽  
Vol 48 (3) ◽  
pp. 436-437
Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo
Keyword(s):  
Biological Clock ◽  
Virgin Female ◽  
Basic Structure ◽  
Fixed Time ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Noctuid Moth ◽  
The Right ◽  
20 Nm ◽  
The Brain

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).

Plasminogen-Activator in Human Early Milk: Its Partial Purification and Characterization

1981 ◽  
Vol 45 (02) ◽  
pp. 121-126 ◽  
Author(s):  
Utako Okamoto ◽  
Noboru Horie ◽  
Yoko Nagamatsu ◽  
Jun-Ichiro Yamamoto
Keyword(s):  
Plasminogen Activator ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Partial Purification ◽  
Order Kinetic ◽  
Diisopropyl Fluorophosphate ◽  
Step Procedure ◽  
Activity Band ◽  
C 50 ◽  
Gel Isoelectric Focusing

SummaryMilk plasminogen-activator was partially purified from human transitional milk collected at about 10 days after delivery, by a five-step procedure involving chloroform treatment, ammonium sulfate precipitation, and column chromatography on Sephadex G-150, CM Sephadex C-50 and DEAE Sephadex A-50. This gave milk-activator with a maximum purification factor of about 2,400-fold with respect to the skimmed milk. The CM Sephadex-step preparation showed, on polyacrylamide gel electrophoresis, a single plasminogen-activator activity band located between the bands of albumin and prealbumin of human serum. This preparation exhibited no kinin forming activity. The activator hydrolyzed acetyl-glycyl-L-lysine methyl ester with similar order kinetic constants to urokinase, and was inhibited strongly by diisopropyl-fluorophosphate. The molecular weight of the activator as estimated by gel filtration was approximately 86,000, the isoelectric points as estimated by gel isoelectric focusing were pH 7.2, 6.9 and 6.6, and the activator activity was not quenched by antiurokinase globulin, indicating that the milk-activator is a different entity from urokinase.

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