In vitro culture of the strobilar stage of Echinococcus granulosus from protoscoleces of human, camel, cattle, sheep and goat origin from Kenya and buffalo origin from India

Protoscoleces from human, camel, cattle, sheep, goat (all from Kenya) and buffalo (from India) hydatid cysts were cultured under identical conditions in vitro using the diphasic culture system of Smyth (1979b). Organisms from all sources grew and segmented in culture. Genital anlagen developed in all cultured worms but further genital differentiation occurred only in cultures of cattle (testes) and camel (testes and genital pore) material. The possible significance of these results is discussed in relation to the general epidemiology of hydatid disease and the potential infectivity of the different strains to man.     

Detection of TRH extended peptides in rat hypothalamus using an antibody raised to pGluHisProGlyLys

An antibody was raised to the synthetic pentapeptide pGluHisProGlyLys which, in radioimmunoassay (RIA), could detect the pentapeptide at a level of 10 fmole per tube and exhibited <0.5 per cent cross reactivity with a series of related peptides. The RIA was used to demonstrate the presence of C-terminally extended forms of thyrotropin releasing hormone (TRH) in rat hypothalamus. After extraction, the endogenous peptides were resolved by gel exclusion chromatography and TRH-extended peptides were revealed by trypsin digestion to release the pentapeptide. The TRH extended peptides occurred in substantial quantity, approximately 11 pmoles/g, indicating that only partial processing of the gene duplicated prohormone takes place.     

Studies on the Bohr Effect of Sheep Hemoglobin

A simple method is described for the measurement of pH changes in hemoglobin solutions on oxygenation and reduction. Data are presented establishing the absence of a Bohr effect in p-chloromercuribenzoate [PCMB] treated hemoglobin. The influence of a number of sulfhydryl inhibitors on the Bohr effect of a hemoglobin solution is reported and an interpretation based on steric factors in the protein is proposed.     

Kinetics and mechanism of catalysis by proteolytic enzymes: The kinetics of hydrolysis of derivatives of l-lysine and S-(beta-aminoethyl)-l-cysteine(thialysine)by bovine trypsin

1. Several esters of the α-N-toluene-p-sulphonyl and N-benzoyl derivatives of l-lysine and S-(β-aminoethyl)-l-cysteine have been synthesized. 2. The kinetics of hydrolysis of the esters by bovine trypsin have been compared. Values of k₀ are similar for corresponding derivatives of the isosteric amino acids and deacylation of an acyl-enzyme appears to be rate-determining in each case. There are, however, some quantitative kinetic differences between the various series of substrates.     

Pyrophosphate and fructose 2,6-bisphosphate effects on glycolysis in pea seed extracts

The participation of pyrophosphate-dependent phosphofructokinase (PPi-PFK) in plant glycolysis was examined using extracts from pea seeds (Pisum sativum L. cv Alaska). Glycolysis starting with fructose 6-phosphate was measured under aerobic conditions as the accumulation of pyruvate. Pyruvate accumulated in a medium containing PPi and adenosine diphosphate at about two-thirds of the rate in a medium containing adenosine diphosphate and adenosine triphosphate (ATP). The PPi-dependent pyruvate accumulation had the same reactant requirements and sensitivity to glycolysis inhibitors, sodium fluoride, and iodoacetamide, as the well-established ATP-dependent glycolysis. Added fructose 2,6-bisphosphate stimulated both the PPi-dependent pyruvate accumulation and PPi-PFK activity whereas this modulator had no effect on ATP-dependent glycolysis or ATP-PFK. Collectively these results demonstrate a PPi-dependent glycolytic pathway in plants which is responsive to fructose 2,6-bisphosphate.     

Effects of Boron Deficiency on Rubidium Uptake and Photosynthesis in the Diatom Cylindrotheca fusiformis

Culturing the diatom Cylindrotheca fusiformis under boron-deficient conditions leads to changes in ⁸⁶Rb uptake and photosynthesis prior to any effect on the rate of cell division. The influx rate of ⁸⁶Rb into boron-deficient cells was 79% of the control rate after 5 to 5.5 hours culture. Despite lowered ⁸⁶Rb influx, however, boron-deficient diatoms accumulated more ⁸⁶Rb than did control cells; this was due to the deficient cells' lower efflux rate. After 24 hours culture, boron-deficient cells had accumulated 30% more ⁸⁶Rb than had control cells, while releasing ⁸⁶Rb at only one-half the control rate. Increased photosynthetic rates were another effect of boron deficiency during this early stage of culture. Prior to 20 hours boron-deficient culture, diatoms had photosynthetic rates 37% greater than those of control cells. Corresponding to the increase in photosynthesis, boron-deficient diatoms had 12% more carbohydrate than control cells after 16 hours culture.     

Dependence creating properties of lipotropin C-fragment (beta-endorphin): evidence for its internal control of behavior

The C-fragment of lipotropin (β-endorphin) possesses reinforcing properties, in that this peptide, like heroin, induced intraventricular self-administering behavior in drug naive rats. Only mild behavioral signs reminiscent of physical dependence were present. After injection into the nucleus raphé magnus, C-Fragment appeared to act as a discriminative stimulus in rats trained to discriminate fentanyl from saline. These data indicate that naturally occuring C-Fragment exerts powerful control of behavior, which may be of significance for the understanding of the mechanisms underlying opiate dependence.     

Biologically active macromolecular forms of oxytocin. [8-Lysine]oxytocin as a suitable ligand.

[8-Lysine]oxytocin was synthesized on a solid support and possessed an oxytocic activity of 100 +/- 6 units mumol on the isolated rat uterus. The epsilon-carbamoyl, epsilon-3-carboxypropionyl and epsilon-3-carboxybutryl derivatives were prepared and had uterotonic activities of 400, 55 and 50 units/mumol respectively. [8-Lysine]oxytocin was coupled unambiguously through the epsilon-amino group to the carboxyl groups of carboxymethylated dextrans or epsilon-3-carboxypropionly-gelatin. The macromolecular oxytocins were water-soluble and retained signigicant oxytocic activity. [8-Lysine]oxytocin should prove a useful ligand for affinity chromatography of oxytocin-binding proteins.     

Comparison of the effect of IL-2 and IL-6 on the lytic activity of purified human peripheral blood large granular lymphocytes

The effects of IL-6 and IL-2 on highly purified, human peripheral blood large granular lymphocytes (LGL) were investigated and compared. IL-6 enhanced LGL NK activity in a dose-dependent manner against K562, however IL-2 was a more potent stimulus of LGL NK function. Neither IL-2 nor IL-6 increased LGL cytotoxic potential in a parallel estimation of heteroconjugated antibody (anti-CD16 x anti-nitrophenyl mAb)-dependent cytotoxicity against nitrophenyl-modified YAC. Unlike IL-2, IL-6 did not significantly induce LGL lymphokine-activated killer activity, LGL proliferation, or LGL lymphokine production. In particular, IL-6 did not stimulate detectable LGL IL-2 production or IL-2R modulation, and mAb to the p75 IL-2R had no effect on IL-6 induction of LGL NK activity. Therefore, in the absence of T cells, IL-6 provided an IL-2-independent signal to LGL that resulted in augmentation of their NK activity without stimulating their proliferation or other LGL functions.