Metal loading and enzymatic degradation of fungal cell walls and chitin

The capacity of chitin (from crab shells) and of fungal cell walls from Trichoderma harzianum to accumulate zinc, cadmium and mercury was studied as well as the effects of adsorbed metals on the enzymatic hydrolysis by Novozym 234 of the two substrates. The total adsorbing capacity with respect to these metals was estimated to be at least 10 mmol kg^–1 chitin (dry weight) and 50 mmol kg^–1 fungal cell walls (dry weight), respectively, at pH 6.1. Enzymatic digestion of fungal cell walls preloaded with mercury and cadmium was significantly reduced, while zinc did not cause any significant inhibition. The effect of metal complexation by chitin on the enzymatic digestion was not as pronounced as for fungal cell walls. This could reflect the fact that chitin sorbed a lower total amount of metals. The inhibitory effect of metals on the enzymatic hydrolysis was caused by the association of the metals with the two substrates and not by the presence of free metals in solution.     

Biogenesis of mitochondria: Defective yeast H+-ATPase assembled in the absence of mitochondrial protein synthesis is membrane associated

We have investigated the extent to which the assembly of the cytoplasmically synthesized subunits of the H⁺-ATPase can proceed in a mtDNA-less (rho°) strain of yeast, which is not capable of mitochondrial protein synthesis. Three of the membrane sector proteins of the yeast H⁺-ATPase are synthesized in the mitochondria, and it is important to determine whether the presence of these subunits is essential for the assembly of the imported subunits to the inner mitochondrial membrane. A monoclonal antibody against the cytoplasmically synthesized -subunit of the H⁺-ATPase was used to immunoprecipitate the assembled subunits of the enzyme complex. Our results indicate that the imported subunits of the H⁺-ATPase can be assembled in this mutant, into a defective complex which could be shown to be associated with the mitochondrial membrane by the analysis of the Arrhenius kinetics of the mutant mitochondrial ATPase activity.This paper is No. 61 in the seriesBiogenesis of Mitochondria. For paper No. 60, see Novitskiet al. (1984).     

Surgical Treatment of Constipation

A 30-year retrospective review of 544,354 Seattle area hospital admissions yielded 25 patients who underwent surgical therapy for the relief of intractable idiopathic constipation. All patients were refractory to conventional medical treatment consisting of the daily use of laxatives, cathartics, emollients or enemas. Long-term follow-up was available for 13 of the 25 patients. All 13 patients had clinical improvement as a result of the operation. This confirms results reported by other authors. Subtotal colectomy and left hemicolectomy are the procedures generally favored.     

Application of solvent extraction to ethanol fermentation

Summary The basic problems of applying solvent extraction to ethanol fermentation were investigated. The selection of solvents was based on the selectivity ratio, which was expressed as the ratio of the ethanol distribution coefficient to the water distribution coefficient. Solvents with high selectivity ratios of more than 50 were found mainly among the alcohols and esters. However, most of these solvents were toxic to ethanol-producing microorganisms. We tried to make a barrier to solvent molecules beneath the surface of gel beads immobilizing the cells as a protection against solvent toxicity. Porapack Q was found to be an effective barrier, and the ethanol production rate of immobilized cells protected with Porapack Q did not change event after the production of eight batches in medium saturated with sec-octanol, which was the most toxic solvent used in our experiments.     

Responsiveness of mesolimbic, mesocortical, septal and hippocampal cholecystokinin and substance P neuronal systems to stress, in the male rat

The effects of acute and subchronic stress upon discrete cholecystokinin (CCK) and Substance P (SP) neuronal systems have been studied. Adult male rats were exposed to foot-shock stress for periods of 2, 4, 10, 30 or 60 min, immediately following which they were decapitated; brains were rapidly removed and frozen, and subsequently microdissected and extracted. CCK and SP were determined by RIA. In the olfactory tubercule, stress had no effect upon CCK content, but induced a rapid depletion of SP. In the prefrontal cortex, increased CCK concentrations were found following 30 min of stress exposure. In the medial septum, foot-shock led to a rapid increase in CCK content, and to a similar but delayed change in SP levels. A rapid rise in CCK concentrations was also seen in the lateral septum, but no stress effect whatsoever upon SP occurred in this structure. In the dentate gyrus, CCK exhibited a biphasic responsiveness to stress, while SP levels were increased only at the later time intervals. These data demonstrate that discrete CCK and SP neuronal systems are responsive to stress, and thereby support a functional role for these peptides in the processing of neural and hormonal signals by the CNS.     

Streptomycin retards the phenotypic maturation of chick myogenic cells

Summary As part of an effort to optimize conditions required for the complete maturation of muscle cells in vitro, we have investigated the effects of the antibiotics penicillin, streptomycin, and Fungizone (amphotericin B) on the development of cultured chick embryo skeletal muscle. It is shown that even low dosages of streptomycin, but not penicillin or Fungizone, retard protein synthesis and accumulation in these cultures. Myosin accumulation was also reduced and the appearance of striations in fused cells was delayed in myotubes formed in medium containing streptomycin. Additional data suggest that this overall retardation of myogenesis is due to the influence of streptomycin on maturing myotubes rather than early proliferation and cell fusion. These results are discussed with regard to recent efforts to promote the full maturation of muscle cells grown in culture. This research was supported by National Institutes of Health Grant NS 155882 and a Task Force on Drug Development Research Contract from The Muscular Dystrophy Association.     

Biophoton emission

The phenomenon of ultraweak photon emission from living systems was further investigated in order to elucidate the physical properties of this radiation and its possible source. We obtained evidence that the light has a high degree of coherence because of (1) its photon count statistics, (2) its spectral distribution, (3) its decay behavior after exposure to light illumination, and (4) its transparency through optically thick materials. Moroever, DNA is apparently at least an important source, since conformational changes induced with ethidium bromide in vivo are clearly reflected by changes of the photon emission of cells. The physical properties of the radiation are described, taking DNA as an exciplex laser system, where a stable state can be reached far from thermal equilibrium at threshold.