Iron hydroxide: Model for enzymes that oxidize proteins

The particles of an iron hydroxide sol were found to be a suitable model for protein-oxidizing enzymes such as peroxidase and polyphenol oxidase. In addition to small molecules such as pyrogallol, human serum proteins, albumin and -globulin, are shown to be substrates of the oxidizing model. The activity is markedly increased by the addition of small amounts of copper to the iron in the particles of the sol. The size and molecular weight of the enzyme model, as well as the number of active centers were determined.     

Immunoglobulin classes of human serum antibodies in vaginal candidiasis

The titre and immunoglobulin class of antibodies against Candida albicans in serum from 60 non-pregnant women was determined. IgG titres up to 132, IgA titres up to 18, and IgM titres up to 14 were detected in 30 women with vaginal candidiasis. Similar titres were found in 20 women harbouring yeasts in the mouth or rectum, and in 10 women who were not harbouring yeasts in the vagina, mouth or rectum. Serum fractionation confirmed that antibodies to C. albicans are found in the three immunoglobulin classes and that these antibodies reside in highest titre in the IgG class. No secretory IgA antibodies against C. albicans were detected in the serum of these women.     

Desmosomes: Their occurrence between adjacent primary oocytes in polyovular follicles in the rabbit

Summary In polyovular, primordial follicles in the rabbit, desmosomes are found between apposing oocyte surfaces. Morphologically these desmosomes correspond closely to those described in epithelia of vertebrates. The desmosomes alternate with other junctions which are probably gap junctions.This work was supported in part by the G.R.S.T. Grant n 75.7.1313     

Structural re-evaluation of the neurosecretory system in the crayfish eyestalk

Summary The topography of the neurosecretory system in the decapod eyestalk has not been precisely delineated with light microscopy. Cobalt iontophoresis and electron microscopy have proved useful in clarifying the microstructure of this system. The sinus gland (sg) of the crayfish eyestalk consists of aggregated axon terminals which end at or near the blood space, lontophoresing cobalt back through the cut base of the sinus glands reveals proximal cell bodies in the eyestalk only in the X organ (Xo) region. Electron microscopy demonstrates that axons from about 115 neurosecretory cell bodies in the Xo form the Xo-sg tract. Intermingled with these Xo somata are smaller non-neurosecretory cell bodies which do not send axons into the sinus gland. One of these exhibits catecholamine fluorescence. Backfilling also reveals a second group of fibres which run from the brain along the optic tract and into the sinus gland. These brain-sg fibres are smaller in diameter than Xo-sg axons and lack neurosecretory vesicles. From these fibres collaterals extend into the eyestalk neuropil, especially in the proximity of the visual elements. The possible function of these non-neurosecretory processes within the sinus gland is discussed.This work was supported by a National Research Council of Canada grant     

The relative effectiveness of three techniques to induce the trophotropic response

The purpose of this study was to examine the relative effectiveness of electromyographic biofeedback training(EMG BFT), remeditation, and progressive muscle relaxation(PMR) in eliciting a relaxation or trophotropic response as measured by frontalis muscle tension, heart rate, electrodermal response, respiration rate, and skin temperature. Fifty-four college students were randomly assigned to one of five groups:(1) control,(2) placebo control,(3) EMG BFT,(4) meditation,(5) PMR. After baseline measures were obtained subjects were trained in 10 30-minute training sessions and posttested. Comparisons by ANOVAs indicated there was a significant decrease in muscle tension in the EMG BFT and meditation groups and significant decreases in respiration rate in the meditation and PMR groups. No other changes were attributed to treatment.     

Built-in co-operativity of oxygen binding by arthropod hemocyanins

Oxygen binding by arthropod hemocyanin from the scorpion Leirus quinquestriatus and the crabs Telphusa fluviatilis and Ocypoda cursor was studied in Ca²⁺, Mg²⁺-free solutions. The binding was found to be co-operative in all three cases. Our results and a re-examination of the literature lead us to conclude that co-operative oxygen binding is a built-in feature common to arthropod hemocyanins, distinguishing them from mollusc hemocyanins where co-operativity is conditional upon the presence of Ca²⁺ or Mg²⁺.     

Neurotubule assembly at substoichiometric nucleotide levels using a GTP regenerating system

Tubulin derived from cold depolymerized bovine microtubules has been gel filtered to obtain a tubulin preparation with only 3% of the tubulin dimers containing exchangeable [³H]-guanine nucleotide. In the presence of acetyl-P and bacterial acetate kinase, this preparation polymerizes to form microtubules which are morphologically indistinguishable from microtubules formed in the presence of excess GTP. The extent of microtubule formation at substoichiometric nucleotide levels using the GTP regenerating system exceeds the extent of assembly obtained with excess GTP. It is concluded that the exchangeable guanine nucleotide site can be virtually unoccupied in intact neurotubules and this finding indicates that GDP can “catalyze” tubule assembly in the presence of a GTP regenerating system.     

THE THICKENED LEPTOID (SIEVE ELEMENT) WALL OF DENDROLIGOTRICHUM (BRYOPHYTA): CYTOCHEMISTRY AND FINE STRUCTURE

Leptoids (sieve elements) of Dendroligotrichum exhibit unevenly thickened lateral walls. The thickened wall areas are predominantly confined to the radial walls. With the light microscope the thickened wall cannot be resolved into distinct layers, but rather is optically homogeneous. Standard histochemical tests reveal that these walls are rich in cellulose (birefringent; IKI-H₂SO₄-positive) with small amounts of polyuronides (toluidine blue-positive) and pectins (hydroxylamine-positive) and are non-lignified. They also contain abundant natural aldehydes as revealed by the Schiff, silver hexamine, and silver proteinate reagents. Aldehyde blockades (sodium borohydrate, sodium chlorite) confirmed the presence of aldehyde groups in the cell wall. At the ultrastructural level, the lateral walls of sieve elements react strongly with uranyl and lead salts and yield little fine structural information. Electron cytochemical localization of aldehydes with silver proteinate revealed three distinct wall regions: outer, middle and inner. The outer and middle regions appeared polylamellate while the inner region contained no reaction product. The nacreous sieve elements of vascular plants are compared to the thickened sieve elements in bryophytes.     

Resolution of optical isomers by high-pressure liquid chromatography: The separation of benzo[a]pyrene trans-diol derivatives

The optical isomers of (±)r-7,t-8-dihydroxy-7,8-dihydrobenzo[a]pyrene and its synthetic precursor (±)r-7,t-8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene were resolved as their di-(−)menthoxyacetates using high-pressure liquid chromatography. Saponification of the resolved diesters yielded the corresponding enantiomers. The specific rotation, CD spectra, and ORD curves are reported. The resolution of these optical isomers permits detailed studies on the enzymatic intermediates and the mechanism of benzo[a]pyrene activation to its carcinogenic form. The method is of general usefulness for the resolution of optical isomers.