Molecular weight of DNA from actinophage MSP2.

Actinophage MSP2 is infectious for Streptomyces venezuelae S13. Based upon electron microscopy of coliphage T4 mixed with MSP2, MSP2 had a head about 48 +/- 2 nm wide and 87 +/- 5 nm long. DNA from polyoma virus and from coliphages T4 and T7 served as reference markers in estimating the molecular weight of MSP2 DNA from sedimentation in sucrose gradients. Denatured MSP2 DNA was estimated to be about 17 x 10(6) and double-stranded MSP2 DNA was about (36 +/- 1.6) x 10(6) in molecular weight.     

Prostaglandin levels in endometrial jet wash specimens in patients with dysmenorrhea before and after indomethacin therapy.

A patient with functional primary dysmenorrhea of over two years duration was subjected to the endometrial jet wash technique during the period of active menstrual flow. Prostaglandin F analysis of the jet washings revealed significantly elevated levels during menstruation over normal control levels. Following indomethacin therapy, jet wash prostaglandin F levels were dramatically reduced and the patient became asymptomatic. A cause and effect relationsship between prostaglandin F and dysmenorrhea is suggested by these studied.     

Identification of specificityH-2.7 as an erythrocyte antigen: Control by an independent locus,H-2G,between theS andD regions

SpecificityH-2.7 is expressed predominantly on erythrocytes and controlled by a gene that maps within theH-2 gene complex at a locus, designated asH-2G, which apparently lies between regionsS andD. Three phenotypes have been observed with respect to this antigen: a) positive by direct test and absorption (haplotypesH-2 ^f ,H-2 ^j ,H-2 ^p ,H-2 ^s ); b) positive only by absorption (H-2 ^k ); and c) negative (H-2 ^b ,H-2 ^d ,H-2 ^q ). New crossover positions have been established for severalH-2 recombinants based on classifications for theH-2G locus.     

The relationship of calcium to receptor-controlled stimulation of phosphatidylinositol turnover. Effects of acetylcholine, adrenaline, calcium ions, cinchocaine and a bivalent cation ionophore on rat parotid-gland fragments.

The possibility that Ca2+ ions are involved in the control of the increased phosphatidylinositol turnover which is provoked by alpha-adrenergic or muscarinic cholinergic stimulation of rat parotid-gland fragments has been investigated. Both types of stimulation provoked phosphatidylinositol breakdown, which was detected either chemically or radiochemically, and provoked a compensatory synthesis of the lipid, detected as an increased rate of incorporation of 32Pi into phosphatidylinositol. Acetylcholine had little effect on the incorporation of labelled glycerol, whereas adrenaline stimulated it significantly, but to a much lower extent than 32P incorporation: this suggests that the response to acetylcholine was entirely accounted for by renewal of the phosphorylinositol head-group of the lipid, but that some synthesis de novo was involved in the response to adrenaline. The responses to both types of stimulation, whether measured as phosphatidylinositol breakdown or as phosphatidylinositol labelling, occurred equally well in incubation media containing 2.5 mm-Ca2+ or 0.2 mm-EGTA [ethanedioxybis(ethylamine)-tetra-acetic acid]. Incubation with a bivalent cation ionophore (A23187) led to a small and more variable increase in phosphatidylinositol labelling with 32Pi, which occurred whether or not Ca2+ was available in the extracellular medium: this was not accompanied by significant phosphatidylinositol breakdown. Cinchocaine, a local anaesthetic, produced parallel increases in the incorporation of Pi and glycerol into phosphatidylinositol. This is compatible with its known ability to inhibit phosphatidate phosphohydrolase (EC 3.1.3.4) and increase phosphatidylinositol synthesis de novo in other cells. These results indicate that the phosphatidylinositol turnover evoked by alpha-adrenergic or muscarinic cholinergic stimuli in rat parotid gland probably does not depend on an influx of Ca2+ into the cells in response to stimulation. This is in marked contrast with the K+ efflux from this tissue, which is controlled by the same receptors, but is strictly dependent on the presence of extracellular Ca2+. The Ca2+-independence of stimulated phosphatidylinositol metabolism may mean that it is controlled through a mode of receptor function different from that which controls other cell responses. Alternatively, it can be interpreted as indicating that stimulated phosphatidylinositol breakdown is intimately involved in the mechanisms of action of alpha-adrenergic and muscarinic cholinergic receptor systems.     

Growth hormone, cyclic nucleotides and the rapid control of translation in heart muscle.

Perfused rat heart incorporated L-[14C]tyrosine into protein at a constant rate for up to 75 min. A purified bovine growth-hormone preparation (1 mug/ml) stimulated the incorporation to a new constant rate that was more than three times the control rate by 10 min after hormone addition to perfusate. The hormone, however, did not alter the intracellular tracer amino acid pool, and the relationship of this to the aminoacyl-tRNA precursor pool is discussed. It is concluded that the increased incorporation largely reflected a rapid increase in protein synthesis at the ribosomes. Measurements of cyclic nucleotide contents during the perfusion showed that these appeared to vary in a systematic way during the perfusion. This strands in contrast with the constant values given by several other parameters measured in this preparation. Futher, the cyclic nucleotide variation seems to be independent of external effectors. The steady-state performance of the heart correlates more closely the [cyclic AMP]/[cyclic GMP] ratio than with the content of the individual cyclic nucleotides. At 10 min after the addition of growth hormone a slight decrese in cyclic AMP content and a large decrease in cyclic GMP were found, suggesting that the hormone's effect in stimulating protein synthesis may be mediated by a decrease in cyclic nucleotide concentrations or an increase in the [cyclic AMP]/[cyclic |p] ratio. The findings are also consistent with an intracellularly directed role for these nucleotides, and the possibility that the cyclic nucleotide changes are an indirect result of growth-hormone action is discussed.     

Movement of neurosecretory product through the anatomical compartments of the neural lobe of the pituitary gland

Summary Electron microscopic studies of the carotid body of the domestic fowl (Gallus gallus domesticus) have shown Type I and Type II cells combined with axons into compact groups. The many Type I cells in the depths of the organ had a body, containing the nucleus, and an elongated, flared process. Some of the Type I cells in the superficial regions tended to be spindle-shaped. Type I cells were characterised by membrane-bound, dense-cored vesicles about 120 nm in diameter. Type II cells invested the Type I cells and had axons embedded in them as in Schwann cells.The fine structure of the carotid body in the domestic fowl resembles that of the Lovebird (Uroloncha domestica) and of various amphibia and mammals. The possibility is discussed that the Type I cells may have a chemoreceptor or a general secretory function, or even both pathway for functions together. The main role of the Type II cells seems to be to provide a of these axons leading to or from Type I cells.The authors are grateful to Mr. R. P. Gould of the Department of Anatomy, Middlesex Hospital Medical School for permission to use some of his and Dr. Hodges' original material in the illustrations. Dr. Hodges also wishes to thank the A.R.C. and the University of London Central Research Fund for financial assistance. We are also most appreciative of the photographic assistance of J. Geary.     

Pancreatic islet cytology of ictaluridae (Teleostei)

Summary The endocrine pancreas of the bullhead catfish, Ictalurus nebulosus, and the channel catfish, I. punctatas was studied by light and electron microscopy. In addition to the usual A, B and D cells, a fourth endocrine cell type was consistently observed in the electron microscope. All endocrine cell types were innervated. The vesicles of most of the nerve endings were ultrastructurally different from typical adrenergic and cholinergic vesicles, strongly suggesting the possibility of a third autonomic neurotransmitter serving as a regulator of catfish islet secretion.Supported in part by PHS grant AM 11407 awarded to Dr. Bryce Munger.     

A light and electron microscopic study of myelopoietic cells in the perihepatic subcapsular region of the liver in the adult aquatic newt,Notophthalmus viridescens

Summary The liver of the newt, Notophthalmus viridescens, consists of several incompletely separated lobes of parenchymal tissue each of which is covered by a perihepatic subcapsular region (PSR) of myeloid tissue. This tissue contains neutrophils and eosinophils in various stages of differentiation. As neutrophils develop from myeloblasts to late neutrophilic myelocytes, two types of granules appear. The primary granules (type of granules formed first) are more electron dense and smaller than the secondary granules (type of granules formed later). The primary granules first appear at the stage designated early neutrophilic myelocyte, and the secondary granules appear at the stage of the maturing neutrophilic myelocyte. The eosinophils present are characterized by much larger granules than those observed in neutrophils. Cells in the PSR which superficially resemble small lymphocytes are primitive stem cells that give rise to neutrophils and eosinophils. The liver PSR is invested by a visceral peritoneum of simple squamous mesothelial cells some of which are ciliated.Supported by ACS IN-105.     

Synthetic analogues of polynucleotides. (Part) XIV. The synthesis of poly (3''-0-carboxymethyl-2''-deoxycytidine) and its interaction with polyinosinic acid.

Poly (3'-O-carboxymethyl-2'-deoxyctidine) (VII) has been synthesised by the polymerisation of 3'-O-carboxymethyl-4-N-phenoxyacety-2'-deoxycytidine (V) and removal of the phenoxyacetyl groups under acidic conditions. V was obtained by the action of 2,4-dinitrophenyl phenylacetate on 3'-O-carboxymethyl-5'-O-triphenylmethyl-2'-deoxycytidine (III) followed by removal of the triphenylmethyl group under carefully controlled acidic conditions. The polymer, VII gave a hypochromic effect of about 20% at 250nm when mixed with poly (1) in 0.2Macetate, pH 5.0. It appeared, therefore, that a complex was formed. Upon heating a solution of this complex there was an initial decrease in optical density followed by a much larger increase to give a Tm of about 60 degrees. Attempts to form the 3'-O-carboxymethyl derivative of 4-N-phenoxyacetyl-5'-O-'triphenylmethyl-2'-deoxycytidine to give a shorter synthetic route to VII were not successful. 3'-O-Carboxymethyl-2'-deoxycytidine was obtained by removal of thetriphenylmethyl group from III. Attempts to polymerise this compound in concentrated aqueous solution with a water-soluble carbodiimide were not successful.