Oxygen consumption by the hermit crab, Clibanarius vittatus (Bosc, 1802) in declining oxygen tensions

1. 1. Oxygen consumption and its relationship to stepwise declining oxygen tension were examined in the common striped hermit crab, Clibanarius vittatus. 2. 2. Weight-specific oxygen consumption varied with body weight (W), according to the equation log V ̇o2 = 2.1639 + (-0.419 log W). 3. 3. Shell-less individuals of 1-2 g wet wt, where found to be oxygen conformers, since oxygen consumption ( V ̇o2) decreased with declining oxygen tensions. At ambient oxygen tensions below 35.4 mmHg, oxygen consumption remained constant, suggesting an increased ventilation. 4. 4. C. vittatus was found to survive in oxygen-free seawater for 5.5 hr, and no significant differences were found in oxygen consumption rates, for shelled and shell-less crabs, measured in water and air. 5. 5. The use of a K1 K2 index of oxygen independence, showed that larger animals were better able to maintain oxygen-independence during hypoxia than smaller individuals. 6. 6. C. vittatus displayed a pattern of no oxygen debt, once returned to normoxia. © 1983.

The influence of temperature on oxygen consumption rates of workers of two leaf cutting ants, Atta laevigata (F. Smith, 1858) and Atta sexdens rubropilosa (Forel, 1908)

1. 1. The oxygen consumption in workers of two simpatric leaf cutting ants, Atta laevigata and Atta sexdens rubropilosa was measured at different temperatures. 2. 2. In the temperature range between 5-35°C, with 5°C increments, the respiratory rates increased with temperature, but the R-T curves of both ants showed neither a marked drop at the low end nor a break at the high end; except between 30 and 35°C. 3. 3. The respiratory rates of A. s. rubropilosa were higher than those of A. laevigata and in the midrange of temperatures, the rates of A. laevigata increased faster than those of A. s. rubropilosa. 4. 4. Q10 values did not indicate regions of compensation for temperature in both ants, but suggested that adjustments may occur at high temperatures (25-35°C), as expected for tropical ants. 5. 5. Temperature variations did not alter significantly the slope of the curve relating oxygen consumption and body weight in both species. © 1982.

The respiratory metabolism of the castes of two leaf cutting ants, Atta laevigata (F. Smith, 1858) and Atta sexdens rubropilosa forel, 1908

1. 1. The respiration of the different castes of two species of leaf-cutting ants, Atta laevigata and Atta sexdens rubropilosa was measured in both workers and sexed forms. 2. 2. The respiratory rates (μl O2/mg(live)/hr) were, in A. laevigata, 0.644 (gardeners), 0.594 (cutters), 0.354 (soldiers), 0.233 (males) and 0.085 (females); in A. s. rubropilosa, 0.803 (gardeners), 0.748 (cutters), 0.510 (soldiers), 0.375 (males) and 0.274 (females), significantly higher than A. laevigata. 3. 3. All castes considered, the b-values of the equation relating oxygen consumption and weight in A. laevigata (0.53) were significantly different from that in A. s. rubropilosa (0.73). © 1981.

Experimental and field record of preferred temperature in the neotropical amphisbaenid Amphisbaena mertensi stauch (reptilia, amphisbaenidae)

1. 1. Temperature preference in experimental thermal gradient in the laboratory was determined and field preferred temperature was recorded, for Amphisbaena mertensi. 2. 2. Mean preferred temperature in 52 experiments averaged 21.4°C which was close to those recorded in 16 specimens measured in the field (21.1°C). 3. 3. Selected temperature varied from 12 to 27°C in the laboratory, and data taken in the field ranged from 18 to 26°C. © 1984.

Hemoglobin patterns in different populations of Synbranchus marmoratus Bloch, 1795 (Pisces, Synbranchidae)

1. 1. Total hemolysates of Synbranchus marmoratus Bloch, 1795 captured at four different sites in the State of São Paulo, Brazil, showed two different hemoglobin phenotypes when submitted to agar-starch gel electrophoresis on glass slides in basic buffer. 2. 2. Phenotype I was characterized by 3 hemoglobin bands. When the total hemolysate was submitted to cellulose acetate electrophoresis in basic buffer containing 6 M urea and β-mercaptoethanol, Phenotype I showed four globins of the α 1, α 2, β and γ types, with 11.9 ± 1.9 g% total hemoglobin, 45.3 ± 3.6% globular volume, and 26.8 ± 4.4% mean corpuscular hemoglobin concentration (MCHC). 3. 3. Phenotype II showed three groups of hemoglobins, with a total of up to 12 hemoglobin bands. When the total hemolysate was submitted to cellulose acetate electrophoresis in basic buffer containing 6 M urea and β-mercaptoethanol, phenotype II showed five types of globins, denoted types α 1, α 2, γ 1, γ 2 and β, having electrophoretic positions different from those of Phenotype I globins, with 18.1 ± 3.3% total hemoglobin, 47.9 ± 6.4% globular volume, and 37.8 ± 4.4% MCHC. 4. 4. The distribution of the specimens having the two hemoglobin phenotypes is associated with the different geomorphological provinces of the State of São Paulo, suggesting the existence of at least two populational groups of Synbranchus marmoratus. © 1986.

Blood oxygen affinity increases during digestion in the South American rattlesnake, Crotalus durissus terrificus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Neuroglia and their roles in central respiratory control; an overview

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Respiratory regulation in workers of the leaf cutting ant Atta sexdens rubropilosa Forel, 1908

1. Respiratory rates of workers of the leaf cutting ant Atta sexdens rubropilosa were measured at different oxygen pressures, at 25°C. 2. In experiments where different ants were used at each of the oxygen pressures, respiration was regulated down to 70.8 mmHg. 3. When the same ants were submitted in sequence to declining pO2, the 'oxygen dependence indexes' (Tang P.S. (1933) Quart. Rev. Biol. 8, 260-274) also suggested a good regulatory capacity. 4. The results are discussed in terms of the variation of the partial pressures of O2 and CO2 that the ants probably encounter when wandering to and from the nest to forage, and when performing their heavy tasks (leaf transport, offspring and fungus care). 5. CO2 rise and O2 fall, from ants' respiration inside the ant hill, may act as the factors that, in a reflex way, keep the spiracles open and increase ventilation and the frequency of CO2 emission to keep the oxygen supply adequate to face the energetic demand of the routine level of activity of the workers, when passing from normoxia (air) to hypoxia (in nest galleries).

A study of multiple mating habit in Atta laevigata based on the DNA content

1. 1. Pure DNA was isolated from the genital organs of the Atta laevigata by the sodium dodecylsulfate method and chloroform-isoamyl alcohol treatment. 2. 2. The DNA content in sexual cells of winged mature subjects gives a new method in the analysis of multiple mating in such species of ants. 3. 3. From the data we concluded that each queen had at least three mates during the nuptial flight. © 1981.

Characterization of the hemoglobins and globins of Synbranchus marmoratus Bloch, 1795 (Pisces, Synbranchidae)

1. 1. Total hemolysates of Synbranchus marmoratus Bloch, 1795, captured in Vitoriana, district of Botucatu, State of São Paulo, Brazil, were submitted to agar-starch gel electrophoresis on glass slides using 42 mM-Tris 1.7 mM EDTA-6.1 mM borate buffer, pH 8.8, for the gel and 10 mM borate-1.7 mM NaOH buffer, pH 8.6, for the cuvette. 2. 2. Three distinct hemoglobin bands were detected, with Hb I being of the cathodic type. 3. 3. Cellulose acetate electrophoresis in 800 mM Tris-2.1 mM EDTA buffer, pH 8.9, containing 6 M urea and 2.25 mM β-mercaptoethanol indicated the presence of four globin chains denoted α 1, α 2, β and γ. 4. 4. It is suggested that the probable tetrameric constitution of the hemoglobin of Synbranchus marmoratus Bloch, 1795 is Hb I (α 2 2γ 2), Hb II (α 2 1γ 2) and Hb III (α 2 1β 2). © 1986.

Respiratory responses of the tropical millipede Plusioporus setiger (Broelemann, 1902) (Spirostreptida: Spirostreptidae) to normoxic and hypoxic conditions

1. 1. Oxygen consumption and its relationship to declining oxygen tension was examined in the tropical spirotreptid millipede, Plusioporus setiger. 2. 2. At 25°C and normoxia, the allometric equations relating the weight-specific oxygen consumption rates and body weight were V ̇O2 = 2.1266 × W-53 for males, and V ̇O2 = 2.0915 × W-64 for females, but no significant difference was detected from the b-values. 3. 3. Plusioporus setiger regulated respiration down to 35.40 mmHg O2 when suddenly exposed to a lowered oxygen tension, or 17.70 mmHg O2, when examined in a stepwise declining oxygen tension. 4. 4. O2 dependence indices ( K1 K2) were relatively low, also expressing regulation, but no relation to size (weight) was recorded. 5. 5. After exposure to hypoxia, P. setiger showed a typical pattern of under repayment, on the return to normoxia. © 1987.

A technique for the determination of the available oxygen in living carp (Cyprinus carpio) muscle

1. 1. A polarographic method for the measurement of the available oxygen in the muscle of living carp by the use of a platinum microelectrode is proposed. 2. 2. The oxygen and the reference electrodes were assembled in a single insertion piece which was implanted in the muscle of a living carp maintained in a special experimental chamber. 3. 3. Curves for normal oxygen levels corresponding to air-saturated water, as well as to a carbogene-saturated water, were obtained. 4. 4. The method can be considered adequate for the measurement of tissue oxygen in living fishes. © 1984.

Uranium metabolism associated with ontogenetic growth of birds: case studies with broilers and ducks

Cobb broilers and domestic ducks, both one-day-old, were treated using ration doped with 20 ppm of uranyl nitrate. Uranium concentrations in the tibia (μg-U/g-bone) were measured by neutron activation analysis as function of the animals’ age, from the neonatal period to maturity. Results show that Uranium and Calcium qualitatively follow the same metabolic pathway, and that adult ducks incorporate on average ten times more Uranium than broilers. Data interpretation shows that the Uranium clearance rate in broilers is substantially higher than that in ducks, suggesting that metabolic characteristics favoring Calcium retention in bone may hinder the elimination of Uranium in ducks. The need for further comparative biochemistry studies between Galliformes and Anseriformes is addressed.

The breathing pattern and the ventilatory response to aquatic and aerial hypoxia and hypercarbia in the frog Pipa carvalhoi

Anuran amphibians are known to exhibit an intermittent pattern of pulmonary ventilation and to exhibit an increased ventilatory response to hypoxia and hypercarbia. However, only a few species have been studied to date. The aquatic frog Pipa carvalhoi inhabits lakes, ponds and marshes that are rich in nutrients but low in O-2. There are no studies of the respiratory pattern of this species and its ventilation during hypoxia or hypercarbia. Accordingly, the aim of the present study was to characterize the breathing pattern and the ventilatory response to aquatic and aerial hypoxia and hypercarbia in this species. With this purpose, pulmonary ventilation (V-1) was directly measured by the pneumotachograph method during normocapnic normoxia to determine the basal respiratory pattern and during aerial and aquatic hypercarbia (5% CO2) and hypoxia (5% O-2). Our data demonstrate that P. carvalhoi exhibits a periodic breathing pattern composed of single events (single breaths) of pulmonary ventilation separated by periods of apnea. The animals had an enhanced V-1 during aerial hypoxia, but not during aquatic hypoxia. This increase was strictly the result of an increase in the breathing frequency. A pronounced increase in V-1 was observed if the animals were simultaneously exposed to aerial and aquatic hypercarbia, whereas small or no ventilatory responses were observed during separately administered aerial or aquatic hypercarbia. P. carvalhoi primarily inhabits an aquatic environment. Nevertheless, it does not respond to low O-2 levels in water, although it does so in air. The observed ventilatory responses to hypercarbia may indicate that this species is similar to other anurans in possessing central chemoreceptors. (C) 2012 Elsevier Inc. All rights reserved.

Hemolymph ion regulation and kinetic characteristics of the gill (Na+, K+)-ATPase in the hermit crab Clibanarius vittatus (Decapoda, Anomura) acclimated to high salinity

We examine hemolymph ion regulation and the kinetic properties of a gill microsomal (Na+, K+)-ATPase from the intertidal hermit crab, Clibanarius vittatus, acclimated to 45 parts per thousand salinity for 10 days. Hemolymph osmolality is hypo-regulated (1102.5 +/- 22.1 mOsm kg(-1) H2O) at 45 parts per thousand but elevated compared to fresh-caught crabs (801.0 +/- 40.1 mOsm kg(-1) H2O). Hemolymph [Na+ (323.0 +/- 2.5 mmol L-1) and [Me2+) (34.6 +/- 1.0 mmol L-1) are hypo-regulated while [Ca2+] (22.5 +/- 0.7 mmol L-1) is hyper-regulated; [K+] is hyper-regulated in fresh-caught crabs (17.4 +/- 0.5 mmol L-1) but hypo-regulated (6.2 +/- 0.7 mmol L-1) at 45 parts per thousand. Protein expression patterns are altered in the 45 parts per thousand-acclimated crabs, although Western blot analyses reveal just a single immunoreactive band, suggesting a single (Na+, K+)-ATPase alpha-subunit isoform, distributed in different density membrane fractions. A high-affinity (Vm = 46.5 +/- 3.5 U mg(-1); K-0.5 = 7.07 +/- 0.01 mu mol L-1) and a low-affinity ATP binding site (Vm = 108.1 +/- 2.5 U mg(-1); K-0.5 = 0.11 +/- 0.3 mmol L-1), both obeying cooperative kinetics, were disclosed. Modulation of (Na+, K+)-ATPase activity by Mg2+, K+ and NH4+ also exhibits site-site interactions, but modulation by Na+ shows Michaelis-Menten kinetics. (Na+, K+)-ATPase activity is synergistically stimulated up to 45% by NH4+ plus K+. Enzyme catalytic efficiency for variable [K+] and fixed [NH4+] is 10-fold greater than for variable [NH4+] and fixed [K+]. Ouabain inhibited approximate to 80% of total ATPase activity (K-I=464.7 +/- 23.2 mu mol L-1), suggesting that ATPases other than (Na+, K+)-ATPase are present. While (Na+, K+)-ATPase activities are similar in fresh-caught (around 142 nmol Pi min(-1) mg(-1)) and 45 parts per thousand-acclimated crabs (around 154 nmol Pi min(-1) mg(-1)), ATP affinity decreases 110-fold and Na+ and K+ affinities increase 2-3-fold in 45 parts per thousand-acclimated crabs. (C) 2012 Elsevier Inc. All rights reserved.