Haemoglobin Bohr effect and lactic acid content of the blood of 2 water-snakes with different degrees of aquatic adaptation.

H. modestus, a water-snake with morphological respiratory adaptation to its habitat, presents haemoglobins with a lower Bohr effect than those of L. miliaris, an aquatic snake without such respiratory adaptations. The difference in blood lactic acid content of the 2 snakes submitted to mechanical stimuli appears to be compatible with the properties of their haemoglobins.     

Antibacterial effect of 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine onStaphylococcus aureus

The mechanism by which a new naphthoquinone derivative, the 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (INQI-E) has antibacterial effect againstStaphylococcus aureus was studied. The interaction of INQI-E with the bacteria was followed by absorption spectroscopy at 323 and 490 nm. The absorption band of INQI-E at 490 nm undergoes a hypochromic shift with a decrease of intensity. This effect was found to be reversible by oxygenation during the first hours of incubation. The participation of an oxidation-reduction process related to the respiratory chain was demonstrated by oxygen consumption. An increase in O₂ uptake and inhibition ofS. aureus growth was observed. Experiments with three inhibitors of the respiratory chain demonstrated that the pathway induced by INQI-E was antimycin-resistant and KCN- and salicylhydroxamic acid (SHAM)-sensitive, which suggests that INQI-E is capable of diverting the normal electron flow to an alternate superoxide-producing route. On the other hand, experiments with Tiron, a specific scavenger of superoxide, hindered the effect of INQI-E againstS. aureus, indicating that the inhibitory growth effect of this quinone-imine is mainly due to the production of the cytotoxic superoxide radical.     

Temperature-controlled alternative respiration and outgrowth rate from conidia ofNeurospora crassa

Summary Incubation of conidia of wild typeNeurospora crassa at temperatures ranging from 25 to 46°C modulates their respiratory type. Between 37 and 41°C, the transient activity of the cyanide-insensitive respiratory pathway parallels, with a maximal extrusion of protons into the medium, the optimal rate of germ tube outgrowth.We are grateful to Mrs Arlette Cattaneo for her competent technical assistance.     

Adaptive respiratory variation in 4 chromosomal species of mole rats

Summary Oxygen and carbon dioxide pressures were measured in subcutaneous gas pockets of 4 chromosomal species of theSpalax ehrenbergi complex. Oxygen pressures of 11.8, 13.6, 16.9, and 17.2 torr and CO₂ pressures of 84.2, 82.9, 80.1, and 64.1 torr were measured for the chromosomal species 2n=52, 54, 58, and 60, respectively. The differences between the 4 chromosomal species in their subcutaneous gas tension appear to reflect adaptive respiratory variation associated with geographic variation in climate. It underlies an important respiratory physiological correlate of ecological speciation in the extremely hypoxic and hypercapnic subterranean environment.     

Action de la (+)-catéchine surPseudomonas fluorescens

Summary The (+)-catechin stimulates the multiplication and the protidic biosynthesis ofP. fluorescens. Its effect seems related to a modification of the terminal respiratory pathway.     

A possible metabolic role foro-diphenoloxidase inMycobacterium leprae

Summary Among mycobacteria,Mycobacterium leprae is unique in its ability to oxidize a variety of diphenols to quinones in vitro. What physiologic roleo-diphenoloxidase has in the organism remained unknown. Reducing substrates like NADPH, NADH and ascorbic acid reacted with the quinone formed from dopa (3,4-dihydroxyphenylalanine); the substrates were oxidized and the quinone was reduced back to diphenol in the process. Since the quinone undergoes reversible oxidation-reduction, diphenoloxidase might serve as an alternative respiratory mechanism inM. leprae for the utilization of other substrates, as has been reported in plants.     

Sensibilité aux UV et photorestauration des typesR etS dePseudomonas fluorescens Mig.

Summary Smooth colonies ofPseudomonas fluorescens are more sensitive to UV than Rough colonies. Resistance to UV is in relation to the presence of a flavinic terminal respiratory system; photoreactivation is more important when terminal respiration is cytochromic.     

A paradoxical effect of 2,4-dinitrophenol in stimulating the rooting of hypocotyl cuttings ofPhaseolus mungo

Summary 2,4-dinitrophenol enhanced root formation on dark-grown hypocotyl cuttings ofPhaseolus mungo. This effect is probably related to uncoupling of oxidative phosphorylation and not through IAA-metabolism as is evident from studies with respiratory inhibitors (Cd²⁺) and non-phenolic uncouplers of oxidative phosphorylation (arsenate).The research has been financed by a grant from United States Department of Agriculture.     

Anoxygene Reaktivierung der Zellvermehrung nach anoxybiotisch hervorgerufener Zytostase (Anabiose)

Summary In cell juice of aerobic fermenting and of only respiring yeast cells, a thermostable respiratory energy reserve is found which under rigorous anoxybiotic conditions effects a generative reactivation in contact with anabiotic fermenting yeast cells, butnot with only respiring ones. Also in cell juice of Jensen sarcoma and other carcinoma tissues, an adequate energy substance is recognized as being able to replace oxygen biologically.     

Note sur l'innervation des branchies chezAnguilla anguilla L.

Summary Maillet's technique demonstrated the innervation of pillar cells of the secondary gill lamellae inAnguilla anguilla L. Nervous control may work in conjunction with an humoral regulation which would make clearer the understanding of the in- and outflux of blood in the respiratory organs.     

Effect of sodium chloride on the respiratory function ofStaphylococcus aureus

Summary Sodium chloride at concentrations below 0.5 M, enhanced the respiratory activity (O₂-consumption) ofStaphylococcus aureus under endogenous and sugar-supported conditions, but did not overcome the inhibitory action of sodium azide. Several sugars, including the glucose analoguea-methylglucoside, and their metabolites enhanced bacterial O₂-consumption, but acetylmethylcarbinol was ineffective.     

Ein bisher nicht erkanntes Chloridzellen-Organ der KarpfenlausArgulus foliaceus L. (Crustacea,Branchiura)

Summary The specialized areas of the carapace ofArgulus foliaceus hitherto known as respiratory areas, are most probably identified as iontransporting epithelia by electron microscope and histochemical investigations.     

Mutagenic effects of sulfur dioxide onSaccharomyces cerevisiae diploid strains

Summary In resting cells of diploidSaccharomyces cerevisiae strains sulfur dioxide induces at very high frequency: a) respiratory deficinet mutants: b) mutants with altered methionine metabolism. In growing cells the following kinds of mutants appear: a) revertants for respiration; b) mutants altered in the methionine metabolism; c) SO₂-resistants. It is suggested that sulfur dioxide acts as a selective agent through the induction SO₂-resistant mutantsAcknowledgments. This investigation was supported by grant of C.N.R., Roma. The authors are grateful to Prof. Domenico L. Palenzona for helpful comments and suggestions.     

Effects of methoprene and juvenile hormone on the oxidative metabolism of isolated mitochondria from flight muscle ofLocusta migratoria L.

Summary In vitro applications of juvenile hormone III and a juvenile hormone analogue, methoprene, were made to mitochondria isolated from dorsal longitudinal flight muscles of adultLocusta migratoria L. Both compounds completely inhibited oxygen consumption at the highest concentrations used. At lower concentrations, state 3 respiration and respiratory control were reduced but the ADP/O ratio was largely unaffected.     

Regulated protein degradation in mitochondria

Various adenosine triphosphate (ATP)-dependent proteases were identified within mitochondria which mediate selective mitochondrial protein degradation and fulfill crucial functions in mitochondrial biogenesis. The matrix-localized PIM1 protease, a homologue of theEscherichia coli Lon protease, is required for respiration and maintenance of mitochondrial genome integrity. Degradation of non-native polypeptides by PIM1 protease depends on the chaperone activity of the mitochondrial Hsp70 system, posing intriguing questions about the relation between the proteolytic system and the folding machinery in mitochondria. The mitochondrial inner membrane harbors two ATP-dependent metallopeptidases, them- and thei-AAA protease, which expose their catalytic sites to opposite membrane surfaces and cooperate in the degradation of inner membrane proteins. In addition to its proteolytic activity, them-AAA protease has chaperone-like activity during the assembly of respiratory and ATP-synthase complexes. It constitutes a quality control system in the inner membrane for membrane-embedded protein complexes.     

An improved electrophoretic method for a screening program for haemoglobinopathies

Summary A method for a screening program for haemoglobinopathies in a starch agar gel mixed with saponin is presented. Normal and abnormal blood containing haemoglobins S, C, I, M Boston, D Punjab, beta thalassaemia major and beta thalassaemia minor, were applied, in a tray with the capacity for 100 samples. The electrophoresis was performed in 45 min using 300 V. This method offers special advantages for the examination of a large number of samples, using a small amount of whole blood and without the previous preparation of haemoglobin solution.Acknowledgments. We would like to express our gratitude to Dr C. Daghlian and Dr Lewis J. Greene for their valuable suggestions. We also thank the Conselho Nacional do Desenvolvimento Científico e Tecnológico, CNPq, for financial support.     

Effect of daminozide on tomato fruit ripening

Summary Fruits of tomato (Lycopersicon esculentum Mill. cv. Fireball) were harvested 32 and 37 days after anthesis and dipped for 30 min in 10,000 ppm daminozide. Ripening of treated fruits, as manifested by an advancement in ethylene production and the respiratory climacteric, was accelerated by up to 7 days over control fruit.Acknowledgment. This investigation was supported by Agriculture Canada and the Ontario Ministry of Agriculture and Food.     

Communicating junctions between pillar cells in the gills of the atlantic hagfish,Myxine glutinosa

Summary In the respiratory lamellae of the gills of the atlantic hagfish,Myxine glutinosa, pillar cells are coupled by communicating junctions. It is suggested that these cells behave like a functional syncytium.Supported by the DFG, SFB 146. The authors are indebted to Drs F. Walvig and H. Stolte for kindly providing the hagfish. The expert technical assistance of G. Voss-Wermbter, Dipl.-Ing., and H. Heidrich is gratefully acknowledged.     

Inhibition of respiratory oxidation of reduced sulfur compounds by intact cells ofThiobacillus denitrificans (strain RT) grown on thiosulfate

Thiobacillus denitrificans strain RT, an obligate sulfur-oxidizing chemolithoautotroph, was grown under microaerophilic conditions with thiosulfate as the only energy source. The rates of tetrathionate, thiosulfate, elemental sulfur (S^o) and sulfite oxidation were measured respirometrically with an oxygen electrode, using actively growing cells. Cells oxidized thiosulfate, elemental sulfur (S^o) and sulfite, but not tetrathionate. The thiosulfateoxidizing activity and elemental sulfur-oxidizing activity (SOA) were almost totally inhibited by 50 M myxothiazol (>80%), an inhibitor of the quinone-cytochrome b region, and by 10 M of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) (>82%). Sulfite-oxidizing activity was also significantly inhibited (>60%) by 50 M myxothiazol and 10 M CCCP. 1 mM KCN totally inhibited (>90%) all respiratory activities. This study confirms that a sulfur-oxidizing activity appears during microaerophilic growth ofThiobacillus denitrificans strain RT on thiosulfate. The SOA is linked to the respiratory chain, probably releasing electrons in the quinone-cytochrome b region.To whom correspondence should be addressed. Submitted by R. Bachofen.     

Temperature dependence of ventilation and O2-extraction in the Kittiwake,Rissa tridactyla

Summary At low ambient temperature the Kittiwake,Rissa tridactyla, increased its oxygen consumption, while lung ventilation remained unchanged. A changed breathing pattern (lower frequency and higher tidal volumes) and an increase in the lung O₂-extraction was responsible for the observed decrease in the ventilatory requirement, which may be important because it reduces the respiratory heat loss during cold exposure.The study was supported by the Danish Natural Science Research Council, Gads Fond, Tipsmidlerne and Norsk Polarinstitutt.