Impulse pattern generation in a crayfish abdominal postural motoneuron

Journal of Comparative Physiology A - It is concluded that burst formation is endogenous to the motoneuron andnot strongly dependent on patterned presynaptic input.     

Idioms of distress: Alternatives in the expression of psychosocial distress: A case study from South India

This paper focuses attention on alternative modes of expressing distress and the need to analyze particular manifestations of distress in relation to personal and cultural meaning complexes as well as the availability and social implications of coexisting idioms of expression. To illustrate this point the case of South Kanarese Havik Brahmin women is presented. These women are described as having a weak social support network and limited opportunities to ventilate feelings and seek counsel outside the household. Alternative means of expressing psychosocial distress resorted to by Havik women are discussed in relation to associated Brahminic values, norms and stereotypes. Somatization is focused upon as an important idiom through which distress is communicated. Idioms of distress more peripheral to the personal or cultural behavioral repertoire of Havik women are considered as adaptive responses in circumstances where other modes of expression fail to communicate distress adequately or provide appropriate coping strategies. The importance of an idioms of distress approach to psychiatric evaluation is noted. Dept. of Psychiatry University of Hawaii     

In vitro microwave effects on human neutrophil precursor cells (CFU-C)

Human marrow cells were irradiated with 2450-MHz CW microwaves in a fluid-filled waveguide irradiation system. Cell exposure was conducted by placing a marrow cell suspension in 20-μl glass microcapillary tubes that were positioned in the exposure chamber, and irradiated at power densities from 31 to 1,000 mW/cm² (with corresponding specific absorption rates of 62 to 2,000 mW/g) for 15 minutes. The temperature of the sample was maintained at a fixed point. Sham-irradiated (SI) and microwave-irradiated (MWI) cells were cultured in a methylcellulose culture system for neutrophil colony proliferation. There was no reduction in neutrophil colony number on days 6–7 or 12–14 in cells exposed at 31 or 62 mW/cm², but as the power density was increased to 1,000 mW/cm², there was a reduction in colony number of MWI cells compared with SI cells. The microwave interaction with the human neutrophil colony-forming cells was apparently not related to temperature rise, or to the state of cell cycle, and was irreversible.     

The hypothalamo-choroidal tract

Summary Light and electron microscopic examination of choroid plexuses from lateral ventricles of water-deprived and subcutaneously or intravenously vasopressin administered rats reveal morphologic changes typical for vasopressin responsive fluid transporting epithelia during hormonal stimulation. Ultrastructural changes noted in both dehydrated and vasopressin treated animals included: the frequent occurrence of choroidal dark cells, dilatation of the lateral and basal intercellular spaces, increased vacuolization of the apical cytoplasm, and a change in microvillar conformation from the normal clavate type to those with a filiform shape. On the basis of the ultrastructural changes observed it is proposed that the choroid plexus be regarded as a target tissue for vasopressin. These findings indicated that a vasopressinmediated transchoroidal cerebrospinal fluid absorption capability exists.Supported by U.S.P.H.S. Grant HD-08867This work submitted as partial requirement for the Master of Science degree in the Department of Anatomy, Colorado State University     

Metabolic interlock between the acetolactate synthase isoenzymes and lysine biosynthesis in Escherichia coli K-12

Summary Some of the strains containing mutations in the genes for the acetolactate synthase isoenzymes are temperature sensitive (ts). Suppression of the acetolactate synthase defect due to one of these mutations suppresses also the ts phenotype; moreover, a genetic cross shows that the two phenotypes cannot be dissociated.The ts phenotype is accompanied by a decreased efficiency of transduction with Pl phage. Observations at the light microscope show formation of abnormal cells. Under specific conditions diaminopimelate stimulates growth and restores normal transduction efficiency. The rate of diaminopimelate formed and excreted by non-growing cells decreases when an acetolactate synthase mutation is present.We give evidence that the ts phenotype is due to an increased formation of lysine from diaminopimelate; this causes a starvation for the latter and therefore cell wall abnormalities. In fact, even at the permissive temperature, the lysine pool is 8x increased in a strain with an acetolactate synthase defect, while a slight decrease in the diaminopimelate pool is observed. Moreover, introduction into a ts strain of a mutation in lysA (the gene coding for diaminopimelate decarboxylase) cures the ts phenotype. Finally among the temperature resistant revertants we found some lysine auxotrophs.     

The molybdenum centre of native xanthine oxidase. Evidence for proton transfer from substrates to the centre and for existence of an anion-binding site.

The observation by Bray & Knowles [Proc. R. Soc. London Ser. A (1968) 302, 351--353] of direct transfer, during the catalytic reaction, of hydrogen atoms from substrate molecules to the enzyme xanthine oxidase was reinvestigated. The experimental phenomenon and its basic interpretation were confirmed and extended. In the reduced functional enzyme, molybdenum(V) interacts with two enzyme-bound protons, which are exchangeable with solvent protons. One of these is coupled to the metal with AHav. 1.4mT and the other with AHav. 0.3mT. The molecule also contains a site for the binding of anions, presumably as ligands of molybdenum. This is shown by effects of nitrate ions on the e.p.r. spectra. The spectra of the nitrate and 1-methylxanthine complexes of the reduced enzyme are very similar to one another, and are designated Rapid type-1 spectra. It is concluded that, in the Michaelis complex, the substrate molecule occupies the anion site, probably being bound to molybdenum via the nitrogen in its 9-position. During the turnover process, hydrogen from the substrate C-8 position, after transfer to the enzyme, appears as the proton more strongly coupled to molybdenum. This proton then exchanges with solvent deuterium with a rate constant of 27s-1, at pH 8.2 and 12 degrees C. It has been confirmed that substrate molecules occupying the anion site do not interfere with observation of the transfer and exchange processes.     

A fermentation process for producing both ethanol and lysine-enriched yeast.

In 18 batch-fermentation experiments, baker's yeast was grown in an enriched mineral medium, containing 10% by weight glucose, at various pH and temperature levels. The pH and temperature are just two representative engineering variables which can be easily varied at negligible cost. The commercial yeast inoculum, 20% by weight or about .16% viable cells, was selected to represent industrial (nonsterile) conditions. Free L-lysine, ethanol, and cell growth were followed in time for each batch run held at a fixed pH and temperature. The maximum free lysine level reached at either 10 1/2 or 24 hr occurred at a pH of 5 and 32 degrees C. At 24 hr, the peak free lysine level, 120 mg/liter, is three times as great as the uncontrolled pH counterpart. In terms of total L-lysine (free plus protein-bound) the peak represents a 25% improvement over the uncontrolled case, based on an average 3.5% lysine level per cell weight. The greatest measured cell level, .9% by weight in the fermentation broth, or a 5 1/2-fold increase over th inoculum, was reached during the 36 degrees C and pH 3 run, while the largest measured ethanol value (3%, or 30% conversion by weight from glucose) was achieved during the 28 degrees C and pH 6 experiment. The optimal lysine run product, however, no less than 15% of the maximum cell and 30% of the maximum ethanol levels.     

Purification of rat liver monoamine oxidase by octyl glucoside extraction and reconstitution

Catalytically active isoenzymes of rat liver monoamine oxidase have been copurified from the outer mitochondrial membrane by a novel method involving repetitive solubilization with octyl-β-d-glucopyranoside followed by reconstitution into lipid vesicles. As analyzed using sodium dodecyl sulfate-gel electrophoresis, the purified enzyme migrates as a single band of protein of molecular weight 60,000. The preparation is capable of metabolizing 576 nmol serotonin and 777 nmol β-phenylethylamine/min/mg protein. Apparent K_m values and sensitivity to the inhibitor clorgyline are very similar for the purified and outer mitochondrial membrane-bound enzyme when determined with the substrates β-phenylethylamine, serotonin, and tyramine.