Effects of altitude on selected blood parameters in populations of the salamander Ambystoma macrodactylum

• 1.1. Adult long-toed salamanders were collected from three sites ranging in elevation from 420 to 2470 m and acclimated at 800 and 2400 m.
• 2.2. Variations in hemoglobin concentration (Hb) and hematocrit (Hct) among populations were analyzed.
• 3.3. Differences among populations were significant in the 800 m acclimation group but not those acclimated at 2400 m.
• 4.4. Significant increases in Hct were associated with acclimation at a higher elevation but concurrent increases in Hb were not observed.

     

Hyaluronidase degradation of hyaluronic acid from different sources: Influence of the hydrolysis conditions on the production and the relative proportions of tetra- and hexasaccharide produced

• 1.1. Hyaluronic acid (HA) can be digested with a Streptomyces hyaluronidase.
• 2.2. The rate of production and the ratio of tetrasaccharide (T) and hexasaccharide (H), studied by HPLC, varied with the temperature and duration of hydrolysis.
• 3.3. The rates of production and the respective amounts of the two oligosaccharides depended on the rheological properties of the HA from different sources.
• 4.4. A close relationship was found between the initial rate of hydrolysis and the intrinsic viscosity of the HA (η_i).
• 5.5. Our data suggest that enzymatic degradation at a given pH value, temperature, and duration of hydrolysis is dependent on the conformation of HA.
• 6.6. Moreover, under given conditions, the relative proportions of the two oligosaccharides depend on the η_i and may also reflect the degree of hydrolysis of the substrate.

     

Alkylating spin labels for spin-labelling of DNA

• 1.1. Five alkylating spin labels, termed SL1, SL2, SL3, SL4 and SL5, have been synthesized and their suitability for spin-labelling of DNA was studied.
• 2.2. It was found that one of them (SL5) lost its free radical moiety under the conditions of spin-labelling, thus giving DNA with no EPR signal.
• 3.3. Two of the spin labels (SL2 and SL4) denatured DNA and therefore they were not appropriate for spin-labelling of double stranded DNA.
• 4.4. The spin labels SL1 and SL3 as well as the recently synthesi/ed HMSL [Raikova et al. (1982) Int. J. Biochem. 14, 41–46.] showed a low destabilizing effect on the DNA double helix and gave spin-labelled DNA with very immobilized EPR spectra (2Azz = 40G).
• 5.5. These three spin labels could be recommended as suitable for application in the EPR spectrometry of DNA.

     

Mitochondria from the ventricle of the marine clam,Mercenaria mercenaria: Substrate preferences and effects of pH and salt concentration on proline oxidation

• 1.1. Mitochondria with high respiratory control ratios (RCR) have been isolated from the ventricle of the marine clam Mercenaria mercenaria.
• 2.2. Proline is the preferred substrate of the mitochondria of the ventricle based on state 3 rates.
• 3.3. Pyruvate, ornithine and succinate are oxidized at rates 3/4 that of proline.
• 4.4. α-Glycerophosphate was oxidized at rates 1/2 that of proline.
• 5.5. The pH optimum for proline oxidation lies between 6.5 and 7.5 based on RCR and ADP/O and between 7.0 and 7.4 based on state 3 rates.
• 6.6. KCl concentrations between 250 and 450 mM gave optimal values for the oxidation of proline based on RCR and state 3 rates.
• 7.7. KCl concentration had little effect on ADP/O between 100 and 850 mM.

     

Enterocyte expression of calbindin,calbindin mRNA and calcium transport increases in jejunal tissue during onset of egg production in the fowl (Gallus domesticus)

• 1.1. Quantitative measurements of calbindin mRNA, calbindin protein and calcium uptake have been made in sectioned intestinal villi to determine the location and cellular characteristics of their expression in immature, point of lay and laying chickens.
• 2.2. Trace amounts of calbindin mRNA were detected by in situ hybridization in enterocytes located around the crypt-villus junction in jejunal tissue taken from immature and point of lay chickens. Large amounts of calbindin mRNA were detected in upper crypt and all villus enterocytes in tissue taken from laying chickens. Maximal levels of calbindin mRNA occurred in the basal third of the villus in laying chickens.
• 3.3. No calbindin was detected immunocytochemically in tissue taken from immature and point of lay chickens. Large amounts of calbindin were expressed in tissue taken from laying chickens. Maximal expression of calbindin in this case occurred in villus tip enterocytes.
• 4.4. Rapid uptake of calcium by tissue taken from laying chickens was twice that found in immature and point of lay birds. Calcium uptake in tissue taken from laying hens was also shown by quantitative autoradiography to take place maximally in villus tip enterocytes.
• 5.5. Regulation ofcalbindin gene expression and the cellular characteristics of calcium transport in laying chickens are discussed in terms of an adaptive response taking place in birds undergoing a daily loss of egg shell calcium.

     

Vitellogenesis in the shrimp,Penaeus vannamei: in vitro studies of the isolated hepatopancreas and ovary

• 1.1. Yolk proteins were isolated from ovaries of the shrimp Penaeus vannamei and used as an antigen for antibody production in rabbits.
• 2.2. Protein synthesis was measured for both the hepatopancreas and the ovary in vitro, and proteins present in both tissues were immunoreactive with the antibodies.
• 3.3. Extracts of shrimp eyestalks inhibited in vitro protein synthesis by both tissues. The inhibitory factor from the eyestalks was heat stable and had a molecular weight of 3300 daltons.

     

Dna breakage and inactivation resulting from hydroxylamine and/or cis-Diamminedichloroplatinum(Ii) interactions with plasmid dna

• 1.1. Occurrence of lesions induced in plasmid DNA by cis-DDP and by HA was quantified both as a transforming activity and as conformation integrity of supercoilcd pBR322 DNA. Fifty per cent decrease of the biological activity of plasmid DNA, not accompanied by measurable change of DNA conformation, was observed after a single exposure of DNA to cis-DDP (1 hr/37°C).
• 2.2. HA induced conversion of supercoiled DNA to other topological forms in a dose-dependent manner.
• 3.3. One- and two-strand DNA breaks were determined electrophoretically with high sensitivity. Cis-DDP exposed DNA relaxed at 30 times lower HA concentration compared to intact DNA.
• 4.4. This effect may be connected with a local distortion of DNA structure at the cis-DDP—DNA bond, which makes possible high effectivity of HA-DNA interaction.
• 5.5. On other hand, biological activity stayed at the 50% level despite breaks induced in DNA.
• 6.6. This finding supports the idea that DNA breaks occur at the locations which were modified during the exposure of DNA to cis-DDP.
• 7.7. The importance of the DNA structure during interaction with HA may be seen during HA-DNA interaction at heat-denaturation of supercoiled DNA. At this condition, the DNA breaks were induced at 100 times lower concentration of HA.
• 8.8. We conclude, on the basis of these results and results published earlier, that local distortion of supercoiled DNA structure, which is caused by the cu-DDP bond, and the local DNA uncoiling caused by heat-denaturation are related to high HA-DNA reactivity.

     

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Interrelationships between gluconeogenesis and uricogenesis in chicken liver

• 1.1. Experiments performed on isolated hepatocytes and perfused liver of starved chickens showed that gluconeogenesis from lactate, glycerol and fructose was inhibited by 22–100% on addition of urate precursors.
• 2.2. The inhibition was associated with an increased rate of urate formation.
• 3.3. 2,4-Dinitrophenol (40 μM), 2-bromooctanoate (2 mM) and 3-mercaptopicolinate (3MPA) (0.5 mM) were inhibitory with respect to gluconeogenesis but did not significantly affect the rate of urate formation.
• 4.4. The possible interrelationships between gluconeogenesis and uricogenesis are considered in terms of a competition for ATP and for other metabolites between the two pathways.
• 5.5. An interplay of both pathways at the level of anion transfer across the inner mitochondrial membrane is also discussed.

     

Metabolic utilization of leucine in a fat and a lean line of chicken

• 1.1. In vivo incorporation into body lipids and breast muscle proteins from l-[U-¹⁴C]leucine was studied in genetically lean or fat male chickens, fed or starved, 1 or 24 hr after intraperitoneal injection.
• 2.2. Lipogensis and portein synthesis from labelled leucine were significantly higher in fat chickens than in lean birds, particularly in those in the fed state.
• 3.3. Radioactivity in the free amino acid pool was greater in fat birds irrespective of the nutritional state.
• 4.4. However, utilization of injected l-[U-¹⁴C]leucine for lipogenesis was no more than 2%.

     

Influence of sex hormones on the chick gastrointestinal transit and emptying

• 1.1. Gastrointestinal (GI) transit and emptying of male and female 15-day-old chickens treated with testosterone, estradiol and progesterone was measured by means of ¹⁴C-polyethylene glycol-4000.
• 2.2. All the administered sex hormones increased GI motility at the shortest time (0.5 and 1 hr) after the marker administration, but decreased GI motility at the longest times (2 and 4 hr). This motor pattern agrees with the known anabolic role of sex hormones.
• 3.3. We conclude that testosterone and estradiol increased GI motility and intestinal inhibitory reflexes. Thus, chicks' and mammals' GI motility were modified by testosterone and estradiol in a similar form.
• 4.4. The effect of progesterone on the chick GI motility was contrary to that observed in mammals. This may happen because of increased inhibitory GI motor reflexes or direct inhibition of visceral smooth muscle activity.
• 5.5. No statistical differences were observed between the sexes, which could be explained by the sexual immaturity of chicks.
• 6.6. Chicks constitute good biological material to study the influence of sex hormones on avian GI motility.

     

l-Leucine intestinal transport at different ages in chicken: Effect of anticoccidial drugs

• 1.1. l-Leucine transport by everted slices of duodenum, jejunum ileum and cecum of 1-, 2- and 3-week-old chickens has been determined.
• 2.2. The effects of the administration with the diet of three anticoccidial drugs: monensin, maduromicin ammonium and nicarbazine have been studied.
• 3.3. In the control animals, there is a reduction on intestinal transport with age, except in the duodenum which is not age-dependent.
• 4.4. Momensine induces an increase on leucine transport in the duodenum and cecum at all ages studied and only in the 3-week-old animals in the jejunum and ileum.
• 5.5. Nicarbazine reduces jejunal absorption of leucine and does not affect the function of the other segments.
• 6.6. Maduromicin ammonium has almost no effect on the absorptive process.

     

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Cell volume regulation in isolated,perfused heart ventricle of the flounder (Platichthys flesus)

• 1.1. The ventricle cells of the flounder (Platichthys flesus) maintained the cell volume regulation mechanism in vitro, when isolated hearts were submitted to a hyposmotic solution.
• 2.2. The initial osmotic swelling of the cells was followed by a secondary shrinking. A new steady state volume (water content) was established in the course of 6 hr. The water content was 3% above control.
• 3.3. The cellular amount of K⁺ and taurine decreased concomitantly with the decline in cellular water.
• 4.4. The decrement in cellular taurine was explained by leakage of taurine, per se, into the perfusion media.

     

Electrophoretic comparison of myosin light chains and parvalbumins of trunk and head muscles from two barbel (Barbus barbus) populations

• 1.1. Myosin light chains and parvalbumins have been compared in several trunk and head muscles from small and large size barbels (Barbus barbus) living in river or reared in hatchery.
• 2.2. These proteins isolated from white, red and ventricle fibres exhibit identical electrophoretic characteristics in the four batches.
• 3.3. The slow fibre content and the parvalbumin distribution are generally similar in river and hatchery barbels of the same size but differ between small and large barbels within a population.
• 4.4. Alterations of the mode of fertilization and breeding conditions do not modify the differentiation of myosin and parvalbumins in barbels.

     

Insulin,glucagon and catecholamine interactions in avian liver explants

• 1.1. A mechanical tissue chopper was used to obtain liver explants (35–75 mg) from 2- to 3-week-old chickens to determine both tissue sensitivity and metabolic effects of isoproterenol, avian insulin and glucagon.
• 2.2. Avian insulin had no effect on lipogenesis; however, lipogenesis was decreased by dibutyryl cyclic AMP. Insulin did not overcome a decrease in lipogenesis caused by catecholamines. Therefore, this control mechanisms is not modulated by insulin.
• 3.3. Preincubation in the presence of glucagon decreased in vitro lipogenesis. Preincubation in the presence of a 19–29 amino acid construct that approximated the radioimmune site for glucagon did not result in a similar effect. Therefore, this site does not relate to the biopotency of the hormone.
• 4.4. A previously noted catecholamine induced decrease in in vitro lipogenesis was verified, showing that points of in vitro regulation are under phosphorylation-dephosphorylation control.
• 5.5. Preincubation of slices (1 hr) with propranolol blocked the inhibition of lipogenesis caused by α and β adrenergic agonists (arterenol or isoproterenol) during a subsequent 2-hr incubation.
• 6.6. Preincubation of slices with either of these agonists decreased lipogenesis even following an extensive washout.
• 7.7. Inhibition could be overcome with propranolol, a β adrenergic antagonist.

     

Amino acid composition and the protein form of procarboxypeptidase a purified from the pancreas of the sei whale Balaenoptera bolealis

• 1.1. Procarboxypeptidase (W-PCPA) was purified from the pancreas of the sei whale Balaenoptera bolealis.
• 2.2. W-PCPA was obtained as a homogeneous protein in polyacylamide gel disc electrophoresis.
• 3.3. W-PCPA has a molecular weight of 75,000.
• 4.4. Amino acid composition of W-PCPA was compared with that of bovine procarboxypeptidase as A S5 (PCPA-S5).
• 5.5. W-PCPA may be two subunits, and the aggregate form may resemble PCPA-S5.