Effect on gluconeogenesis of mutants blocking two mitochondrial transport systems in the yeast Saccharomyces cerevisiae

Two mutants of Saccharomyces cerevisiae, ccr1 and tpy1, have been found to interfere with the transport of small molecules across the inner mitochondrial membrane. Both also have the effect of interfering with the synthesis of a number of cytoplasmically located enzymes involved in gluconeogenesis, even when the cells are released from glucose repression. The ccr1 mutant, defective in the transport of dicarboxylic acids across the inner membrane, represses the synthesis of gluconeogenic enzymes almost totally, but synthesis can be induced on complete medium without a carbon source. This mutant has low levels of intracellular malate under all growth conditions tested. The tpy1 mutant, defective in the transport of pyruvate across the inner membrane, shows repression of gluconeogenesis enzymes under some growth conditions, particularly high levels of ethanol in the medium. These conditions also lead to low levels of malate in the cells. Intracellular levels of malate in these mutants, and in the wild type, are correlated with the levels of gluconeogenic enzymes present. The ability of isolated mutant mitochondria to phosphorylate ADP is shown to be consistent with the interpretation that they are defective in inner membrane transport, although as yet no evidence is available that these defects are the primary lesions in the two mutants. The data are consistent with two general models. In one, the exhaustion of an extramitochondrial corepressor or introduction of a coinducer by mitochondrial activity triggers the induction of gluconeogenic enzyme synthesis. In the second, the mitochondria themselves trigger this induction, but only when the tricarboxylic acid cycle is able to operate at a high level.

Validity and cost-effectiveness of the Gonozyme test in the diagnosis of gonorrhea

Although bacterial culture is considered to provide the most definitive diagnosis of gonorrhea, it has limitations when specimens must be transported long distances. A study was carried out to evaluate the validity and cost-effectiveness of an alternative method of diagnosing gonorrhea, the Gonozyme test, a commercially available enzyme immunoassay. Urogenital specimens from 100 men and 100 women with symptoms suggestive of or a history of exposure to gonorrhea were tested for the presence of Neisseria gonorrhoeae by means of bacterial culture and for gonococcal antigen with the Gonozyme test. The specimens from the men were also examined by means of microscopy of Gram-stained smears. The sensitivity and specificity of the Gonozyme test with reference to culture results were 95.6% and 97.4% respectively in the men and 84.2% and 98.7% in the women. The predictive value of a positive result was 91.6% in the men and 94.1% in the women, and the predictive value of a negative result 98.6% in the men and 96.3% in the women. The cost-effectiveness of the Gonozyme test was higher than that of bacterial culture in this population, which had a high prevalence rate of gonorrhea (23% in the men and 19% in the women). The Gonozyme test would be an adequate alternative to culture for the diagnosis of gonorrhea and contact tracing in areas far from diagnostic laboratories.

[Bone nocardiosis. Apropos of a case in a young child]

Osteitis of the forearm due to Nocardia asteroides was noted in an 8 year old tunisian boy 14 months after an open fracture. This observation of direct inoculation of bone by Nocardia asteroides was atypical because of the remarkable nature of the hyperostotic reaction.

[Bacteriologic surveillance of patients with infectious endocarditis. Value and limitations of the determination of minimal inhibitory concentration and serum bactericidal activity]

This is a retrospective study of the records of 17 patients who suffered from infectious endocarditis with positive blood cultures, and concerns the possibilities of predicting immediate infectious signs in patients:--by testing each of the antibiotics used for the minimal inhibitory concentration;--by determining the peak of the serum bactericidal activity of patients. All the patients were under observation, as outpatients, for more than a year and proved completely cured of their infectious endocarditis. A satisfactory minimal inhibitory concentration does not necessarily prevent an infectious evolution in the immediate future. The determination of the peak serum bactericidal activity does not reflect faithfully and instantaneously the anti-infectious action of the treatment; this is shown by the excellent and rapid evolution 13 times out 20 although serum bactericidal activity was considered insufficient (less than 1/8). This level of 1/8 is not a guarantee of therapeutic efficiency. Finally the antiinfectious treatment has been, in the majority of cases, determined by clinical signs and in very few cases by serum bactericidal activity results.

Alcohol dehydrogenase II and fructose-1,6-bisphosphatase appear to be co-regulated in wild-type yeast

An activity gel assay for fructose-1,6-bisphosphatase (FBP), the enzyme catalyzing the final step in gluconeogenesis in yeast, has been developed which can be used in conjunction with spectrophotometric assays to show that it is tightly co-regulated with the inducible alcohol dehydrogenase, ADHII. Both enzymes are repressed coordinately in aerobically grown yeast by the addition of high levels of glucose or ethanol, and induced on minimal medium by the addition of yeast extract. A mutant deficient in FBP segregates independently of the ADHII structural gene locus. This phenomenon is of interest because of the discovery of Ciriacy [(1979) Mol. Gen. Genet. 176, 427-431] of mutants (ccr, or carbon catabolite repression) which repress both FBP and ADHII simultaneously, along with several other enzymes.

Effect of mutants and inhibitors on mitochondrial transport systems in vivo in yeast

We have reported elsewhere (Wills, C. and Martin, T. (1984) Biochim. Biophys. Acta 782, 274-284) that one or more mitochondrial transport systems may be involved in the regulation of the inducible alcohol dehydrogenase of yeast, ADH-II. In order to investigate this phenomenon further, it was necessary to determine which of these systems operate in the cell in vivo. We give in this paper preliminary evidence that inhibitors of the malate-phosphate (n-butyl malonate), malate-citrate (hydroxycitrate) and malate-alpha-ketoglutarate (aminooxyacetate or cycloserine) transport systems all operate in vivo. While the demonstration of the in vivo inhibitory activity of n-butyl malonate and hydroxycitrate is entirely by physiological methods, that of the transaminase inhibitors aminooxyacetate and cycloserine depends in part on the isolation of mutants capable of growth on glycerol in minimal medium. On this medium these mutants depend on the malate-aspartate shuttle for growth, and as expected the transaminase inhibitors prevent their growth. Two of the mutants show an enhanced rate of mitochondrial glutamate uptake. A preliminary survey of the properties of the glycerol growth mutants is presented, showing that the probable mode of action of these mutants is an increase in the efficiency of the malate-aspartate shuttle.

Extracellular conditions affecting the induction of yeast alcohol dehydrogenase II

The alcohol dehydrogenases in yeast form one of the best-understood eukaryotic regulatory systems at the genetic level, but very little is known about their regulation at the biochemical level. We report on a simple whole-cell assay system for the induction of the inducible isozyme, alcohol dehydrogenase II, which has been used to show that no single compound added to the medium is responsible for the induction. The compounds which show the greatest inducing activity--malate, glutamate and fumarate--are all directly or indirectly involved in mitochondrial transport systems. No single compound can be purified from extracts of yeast cells to give inducing activity at low concentrations, suggesting that the inducing activity is an endogenous function of the cell. Tentative models for regulation of this isozyme involving the mitochondrion are proposed, and suggestions are made for testing these models further.

Hyperparathyroidism in pregnancy: case report and review of the literature

The apparent incidence of hyperparathyroidism (HPT) is low in pregnancy but will likely increase now that more asymptomatic HPT is being diagnosed. However, since the serum calcium levels are decreased in pregnant women, mild primary HPT may go unrecognized. In untreated cases of HPT, complications during pregnancy or during the neonatal period have included spontaneous abortion, stillbirth, neonatal death, neonatal tetany and hypercalcemia. A review of the literature indicates a substantial improvement in fetal outcome when parathyroidectomy is done during pregnancy, as in the case reported here. Therefore, parathyroidectomy is the treatment of choice when the diagnosis is made during pregnancy, although oral phosphate therapy may be an alternative if surgery is contraindicated.

The transfer test: a new screening procedure for thrombotic diseases

The transfer test (TT) measures by means of thromboelastography the capacity of a plasma to shorten the coagulation time of a control plasma. The value of the TT was compared to that of fibrin(ogen), degradation products (FDP), and ethanol gelatin test (EGT) in various diseases (group I), in confirmed deep venous thrombosis (group II), and in confirmed pulmonary embolism (group III). In 211 consecutive patients admitted for various diseases the results of the TT, FDP, and EGT were abnormal in 12.3, 11.3, and 66.6%, respectively, of the cases. In 59 consecutive patients with deep venous thrombosis confirmed by radiological phlebography the results of TT, FDP, and EGT were abnormal at admission time in 96.6, 89.8, and 44%, respectively, of the cases. In 45 consecutive patients with pulmonary embolism confirmed by lung scintigraphy the results of TT, FDP, and EGT were abnormal at admission time in 97.7, 97.6, and 88%, respectively, of the cases. Among the three parameters which were evaluated, the TT seems to be the most sensitive screening procedure for thrombotic diseases. A normal result of TT is a strong argument against a recent thrombotic venous phenomenon.

Emergency aortic valve replacement in Brucella endocarditis: report of two cases

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Relations between circulating levels of testosterone, 17 beta-estradiol, androstenedione, dehydroepiandrosterone sulfate, and androgenic receptor content of cytosol in benign prostatic hyperplasia

Cytoplasmic androgen receptor content was determined in 26 patients with benign prostatic hyperplasia using methyltrienolone (R 1881) as the radioactive ligand. Their concentrations were compared with patient age, adenoma weight, and total circulating concentrations of testosterone, 17 beta-estradiol (17 beta-E2), androstenedione (A) and dehydroepiandrosterone sulfate (DHEA-S). Statistically significant inverse correlations were noted between adenoma weight and receptor content (p less than 0.05) and significant direct correlations between DHEA-S and receptor concentration (p less than 0.05), although the levels of this androgen were similar to those observed in a 'normal' population of the same age. The possible implications of these findings relative to the pathogenesis of the disease are discussed.

Shigellosis with bacteremia: a report of two cases and a review of the literature

It is widely believed by both physicians and microbiologists that bacteremia is a rare event in shigellosis. We report two cases of shigellosis with positive blood cultures and review 68 cases reported in the literature between 1963 and 1981. We suggest that detection of bacteremia in shigellosis may be facilitated by a greater awareness of the following findings. 1. Eighty-seven percent of all cases of shigellosis with bacteremia reported in the literature during the 18-year period reviewed occurred in pediatric patients under 16 years of age. The majority of detected shigellemia cases were in children under 5 years of age. 2. Bacteremia is frequently intermittent and its detection is aided by collection of serial blood cultures with an adequate volume of blood. 3. Positive blood cultures were obtained most frequently on Days 1 to 2 and on Days 5 to 7 following onset of symptoms. 4. The case fatality rate of reported shigellemia cases was 46%. Although some of these findings may reflect a patient selection bias of cases reported in the literature, we believe that a greater awareness among clinicians and microbiologists of the potential value of blood cultures in the diagnosis and management of shigellosis will eventually lead to a better understanding of the pathogenesis of this infectious disease.

Family outbreak of yersiniosis

Yersinia enterocolitica biotype 1, serotype O:21 was isolated from feces or rectal washings of three members of one family in northwestern Saskatchewan. The three isolates gave positive pathogenicity tests in guinea pigs with cultures grown at 22 degrees C as inoculum. All three cases showed clinical symptoms consistent with yersiniosis. All three cases had symptoms of diarrhea and abdominal pain, and two cases had recorded fever. In two cases, appendicitis was initially suspect. One case with ileitis and peritonitis was fatal. The environmental source of the infection was not found, but river water, milk, and person-to-person spread are discussed as possible sources of the infections. The need for microbiology laboratories to culture stool specimens specifically for Y. enterocolitica, using cold-enrichment techniques is emphasized. This family outbreak of yersiniosis provides further evidence that certain biotype 1 strains of Y. enterocolitica are pathogenic.

Tularemia in Canada with a focus on Saskatchewan

Although rare among humans in Canada, tularemia is often endemic in wildlife. The inhabitants of rural areas are especially likely to be exposed to the causative bacterium, Francisella tularensis, through trapping or through the bites of arthropods. Muskrats have replaced rabbits as the principal source of infection, as illustrated by a familial outbreak of oropharyngeal tularemia in Saskatchewan. In humans the disease has six distinct forms and can be asymptomatic, but it generally comes to medical attention as fever, persistent ulcers and enlarged lymph nodes. Serologic tests will confirm the diagnosis.Bien que la tularémie soit rare chez l'homme au Canada, elle existe souvent à l'état endémique parmi les animaux sauvages. Les habitants des régions rurales sont particuliérement susceptibles d'être exposés à l'agent étiologique, Francisella tularensis, lors du trappage ou par les morsures d'arthropodes. Le rat musqué a maintenant remplacé le lapin comme principale source d'infection, tel que l'illustre une poussée de tularémie oropharyngienne chez une famille de Saskatchewan. Chez l'humain la maladie prend six formes distinctes, et elle peut être asymptomatique, mais elle se présente généralement à l'attention du médecin comme une fièvre accompagnée d'ulcères persistants et d'une tuméfaction ganglionnaire. Les épreuves sérologiques confirment le diagnostic.

Arming of mononuclear phagocytes by eosinophil peroxidase bound to Staphylococcus aureus

When eosinophil peroxidase (EPO) was incubated with Staphylococcus aureus (staph) approximately 40% remained firmly bound to the bacteria as indicated by guaiacol assay. The staph-EPO complex was killed readily by concentrations of H2O2 and a halide that did not alter the viability of control (non-EPO-coated) organisms or organisms pretreated with another basic protein, protamine. This toxic effect was abolished by omitting either H2O2 or halide and was inhibited by azide, cyanide, or aminotriazole. Peroxidase activity was evident on the surface of the organism after ingestion by rabbit blood monocytes. The staph-EPO complex was killed at a greater rate by both rabbit blood monocytes and alveolar macrophages than were control organisms, an effect that did not appear to be secondary to improved phagocytosis. The peroxidase inhibitor azide inhibited the killing of staph-EPO by these mononuclear phagocytes without affecting the killing of control staphylococci; in the presence azide, the killing curve with staph-EPO returned to that seen with control organisms. Further, aerosolized EPO-coated organisms were cleared more rapidly from rat lung than were uncoated organisms or organisms pretreated with protamine. These findings suggest mononuclear phagocytes can utilize EPO bound to the surface of ingested microorganisms to enhance their microbicidal activity.

Functional mutants of yeast alcohol dehydrogenase

Selection of petite strains of yeast (that is, strains unable to respire aerobically) on media containing allyl alcohol will result in enrichment for mutants at the ADC1 locus. This locus codes for the constitutive alcohol dehydrogenase, ADH-I, which is primarily responsible for the production of ethanol in yeast. The mutant enzymes are functional, and confer resistance to allyl alcohol on the cell by shifting the NAD-NADH balance in the direction of NADH. These mutants exhibit altered Km's for cofactor, substrate, or both, and often have altered Vmax's. In this paper, the methodology for obtaining these mutants and for determining the amino acid substitutions responsible for these changes is presented. Several new mutants have been at least approximately localized, and one, DB-AA3-N15, has been shown to be due to the substitution of an arginine for a tryptophan at position 54. This substitution would be expected, by analogy with the known tertiary structure of the horse liver alcohol dehydrogenase, to decrease the hydrophobic environment of the active site pocket. The substitution has a pronounced effect on the Km for ethanol, but far less on that for acetaldehyde. The current status of investigation of other classes of functional mutants of this enzyme, and the potential both for selection of useful variants of this molecule and for an increase understanding of its function are discussed.

Arming of mononuclear phagocytes by eosinophil peroxidase bound to Staphylococcus aureus

When eosinophil peroxidase (EPO) was incubated with Staphylococcus aureus (staph) approximately 40% remained firmly bound to the bacteria as indicated by guaiacol assay. The staph-EPO complex was killed readily by concentrations of H2O2 and a halide that did not alter the viability of control (non-EPO-coated) organisms or organisms pretreated with another basic protein, protamine. This toxic effect was abolished by omitting either H2O2 or halide and was inhibited by azide, cyanide, or aminotriazole. Peroxidase activity was evident on the surface of the organism after ingestion by rabbit blood monocytes. The staph-EPO complex was killed at a greater rate by both rabbit blood monocytes and alveolar macrophages than were control organisms, an effect that did not appear to be secondary to improved phagocytosis. The peroxidase inhibitor azide inhibited the killing of staph-EPO by these mononuclear phagocytes without affecting the killing of control staphylococci; in the presence azide, the killing curve with staph-EPO returned to that seen with control organisms. Further, aerosolized EPO-coated organisms were cleared more rapidly from rat lung than were uncoated organisms or organisms pretreated with protamine. These findings suggest mononuclear phagocytes can utilize EPO bound to the surface of ingested microorganisms to enhance their microbicidal activity.

Rapid, quantitative analysis of cell cycle stages of cold-sensitive derivatives of the Chinese hamster cell line CHO-K1

Cell cycle parameters of two cold-sensitive Chinese hamster cell lines have been determined by flow cytometric analysis of cell populations stained with the DNA specific fluorochrome mithramycin. The most striking finding is a depletion of S phase cells, detectable as early as 12 h after a shift to the nonpermissive temperature of 30.0 degrees C and complete by 24 h following the shift. There is a substantial increase in the proportion of cells in the G1 phase of the cell cycle compared to wild type cells under identical conditions but, surprisingly, the proportion of cells having a G2/M DNA content is quite similar in the two populations. The proportion of tetraploid cells present in these populations is not sufficient to account for this observation. Reversibility of the cold-induced block was tested by returning cells held for three days at the nonpermissive temperature to the permissive temperature. Cells having a G1 content of DNA do reenter the S phase, beginning approximately 8 h after a return to the permissive temperature.

HnRNP core proteins: synthesis, turnover and intracellular distribution

Our present data indicate that the Mr 34-40,000 polypeptides which are involved in the binding of a large fraction of hnRNA sequences, including mRNA, are for the most part metabolically stable species in mouse ascites tumor cells. An exception to this generalization is the smallest of 30S RNP core polypeptides, the Mr 34,000 protein, which has a relatively high turnover rate. The relationship of the various synthesis and degradation rates to the physiological state of mammalian cells remains to be determined, as does the pathway of assembly and disassembly of RNP substructures during re-utilization of the proteins and during their turnover. Immunofluorescent studies, which have confirmed the expected nucleoplasmic or euchromatic localization of the RNP core proteins, have also indicated that these species are stable during mitosis, at which time they are dispersed through the cell away from the condensed chromosomes. The proteins appear to relocate in the nucleus as soon as the nuclear envelope is reformed.

Divalent cation binding to phospholipid veiscles. Dependence on temperature and lipid fluidity

Mn2+ binding to vesicles prepared from several different species of anionic phospholipids was determined as a function of temperature by electron paramagnetic resonance (EPR). The Mn2+ affinities of phosphatidylserine, cardiolipin and egg yolk phosphatidylglycerol all increased monitonically with temperature. Vesicles prepared from hydrogenated and natural (bovine) phosphatidylserine were monitored with respect to hydrocarbon chain fluidity as well as Mn2+ binding. Contrary to expectations based on surface potential considerations, the affinity of phosphatidylserine for divalent cations was apparently not lowered in going from the gel state to the lipid crystalline state of the bilayer. The results are instead consistent with an enhancement in cation affinity with increased lipid fluidity. Dipalmitoyl phosphatidylglycerol vesicle fluidity and Mn2+ binding were also studied with EPR. A large reduction in the measured Mn2+ affinity accompained melting of the phospholipid, but observed hysteresis in the temperature dependence of the binding render uncertain any simple explanation based on changes in surface potential. Supplementary light scattering data indicated that vesicle aggregation was involved in the hysteresis phenomena.

Retention of mRNA on the endoplasmic reticulum membranes after in vivo disassembly of polysomes by an inhibitor of initiation

Membrane-bound ribosomes and messenger RNA remained associated with the microsomal membranes of human fibroblasts after cultures were treated with Verrucarin A, an inhibitor of initiation which led to extensive run-off of ribosomes from polysomal structures. When a membrane fraction from Verrucarin-treated cells containing such inactive ribosomes and mRNA was suspended in a medium of high salt concentration, extensive release of ribosomal subunits occurred without the need for puromycin. The mRNA nevertheless remained associated with the membranes. These results add support to the conclusion that, in human fibroblasts, mRNA is bound directly to ER membranes, independently of the ribosomes and nascent polypeptide chains.