Metabolism of secondary alcohols in Drosophila melanogaster: Effects on alcohol dehydrogenase

• 1.1. In vivo metabolism of a secondary alcohol in Drosophila melanogaster and its effects on alcohol dehydrogenase (ADH) have been studied.
• 2.2. ADH-mediated breakdown of the secondary alcohol, propan-2-ol, was the main source of the acetone produced.
• 3.3. Acetone formation declined and stopped ultimately, suggesting inhibition of ADH activity in vivo which has been confirmed in in vitro studies.
• 4.4. A powerful ketone-trapping agent, semicarbazide, did not restore the ADH activity in vitro, whereas aldehyde substrates of ADH did restore activity.
• 5.5. The final formation of a dead-end ADH:NAD-acetone ternary complex has been proposed and its consequences discussed.

     

Effects of milk fat,unhydrogenated and partially hydrogenated vegetable oils on serum lipoproteins in growing pigs

• 1.1. Crossbred Yorkshire (Yorkshire × Landrace) pigs were fed butter oil, cream, low erucic acid rapeseed oil, sunflower oil and partially hydrogenated sunflower oil in amounts representing 30% of energy for periods of up to 13 weeks.
• 2.2. After 13 wk of feeding serum total cholesterol levels of pigs fed milk fat were significantly higher than of pigs fed vegetable oils.
• 3.3. The difference in cholesterol was mainly due to an increase in the density range of 1.063–1.125 g/ml containing pig LDL₂ and some HDL.
• 4.4. A shift towards smaller LDL particle size was apparent in pigs fed milk fat.
• 5.5. The effects of dietary trans fatty acids did not differ from cis polyunsaturated or monounsaturated fatty acids.

     

A novel inhibitor of glycogen phosphorylase from crayfish hepatopancreas

• 1.1. A novel glycogen phosphorylase inhibitor was partially purified from crayfish hepatopancreas.
• 2.2. The inhibitor was found only in two species of crayfish examined, and not in lobster, fresh and salt water clams, mussels or cockroaches.
• 3.3. The inhibitor is a small protein (M_r = 23,000) which did not show proteolytic activity.
• 4.4. Preliminary kinetic analysis of the inhibitory mechanism indicated that it bound to both glycogen and the glycogen phosphorylase protein.
• 5.5. Inhibitor binding to glycogen resulted in a competitive inhibition pattern with respect to glycogen phosphorylase (inhibition constant of ca 10 μg/ml).
• 6.6. The inhibitor also bound glycogen phosphorylase directly with a binding coefficient of 100 μg/ml resulting in a partially non-competitive inhibition pattern with respect to phosphate.

     

Echinochrome-A as a bactericidal substance in the coelomic fluid of Echinus esculentus (L.)

• 1.1. The concentrations of echinochrome-A in coelomic fluid from healthy specimens of the sea urchin Echinus esculentus (L.) ranged from 3 to 60 μg/ml, with a geometric mean of 14 μg/ml.
• 2.2. Echinochrome-A (50 μg/ml) dissolved in sea water, with the aid of mammalian proteins as dispersants, was bactericidal or bacteriostatic towards six out of seven strains of marine gram-negative and gram-positive bacteria.
• 3.3. Echinochrome-A is suggested as a major factor in the bactericidal activity of coelomic fluid from E. esculentus.

     

Changes in serum immunoglobulin M (IgM) concentrations during early development of chum salmon (Oncorhynchus keta) as determined by sensitive elisa technique

• 1.1. A specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the measurement of low levels of serum immunoglobulin M (IgM) of chum salmon Oncorhynchus keta.
• 2.2. In this assay, 5 μl serum was enough to measure the concentration of IgM and the minimum detectable concentration of serum IgM was about 5 ng/ml.
• 3.3. Coefficients of variation within and between assays ranged from 2.90 to 9.61%.
• 4.4. IgM concentrations remained at low level (< 300 ng/ml) until 40 days after hatching and then increased rapidly at the period of emergence (48 days after hatching).

     

Acute stress suppresses plasma estradiol levels in female alligators (Alligator mississippiensis)

• 1.1. Five adult, female alligators (Alligator mississippiensis) were captured at night during the breeding season, and a blood sample taken within 5 min of capture.
• 2.2. The alligators were physically restrained (tied to boards) and additional blood samples taken at 4, 8, 12, 16, 22, 28, 38, and 48 hr after capture. After the last blood sample was collected the animals were released.
• 3.3. Plasma estradiol-17β and corticosterone were measured by radioimmunoassay. Estradiol declined significantly from initial values by 22 hr post capture, but remained unchanged for 48 hr.
• 4.4. Plasma corticosterone rose from a mean of 0.8 ng/ml at capture to 12.6 ng/ml after 4 hr. Corticosterone continued to rise up to 16 hr then declined after 22 hr. From 28 until 48 hr corticosterone again increased significantly.
• 5.5. These results demonstrate that acute stress in female alligators causes significant suppression of plasma estradiol and a biphasic pattern of corticosterone secretion.

     

Changes in free amino acid composition in haemolymph of larvae of the wax moth,Galleria mellon ella L., during cold acclimation

• 1.1. Free amino acids were analysed in the haemolymph of Galleria mellonella larvae by HPLC chromatography with o-phthaldialdehyde (OPA)-l-thio-β-d-glucose as derivatization agent.
• 2.2. Fourteen primary amino acids were detected among which glutamine, alanine, γ-aminobutyric acid (GABA) and glycine predominated and constituted 67.7% of the amino acids found.
• 3.3. The concentration of GABA increased significantly with the age of larvae entering the wandering phase and reached a maximum during metamorphosis.
• 4.4. Analysis of cold-acclimated larvae revealed a net increase of free primary amino acids from 96 to 151.8 μmol/ml during consecutive acclimation to 0°C within 20 days and to 205.4μmol/ml during cold shock injury at 0°C (3 hr).
• 5.5. The bulk of this increase was accounted for by alanine, glycine, phenylalanine and lysine.

     

Bovine serum sialic acid: Age-related changes in type and content

• 1.1. The sialic acid content of newborn calf serum (4.8 μmol/ml) is approx. 3-fold higher than that of mature animals (1.4 μmol/ml) and decreases to 2.4 μmol/ml at 20 days of age. Colostrum-fed and colostrum-deprived calves have similar levels of sialic acid from birth to 14 days of age.
• 2.2. The high level of sialic acid in newborn calf serum is due predominantly to N-acetylneuraminic acid, since this sialic acid accounts for 93% of the total and since <5% of the sialic acid is O-acetylated.
• 3.3. Comparison of day 0 and day 20 serum by gel filtration and by SDS polyacrylamide gel electrophoresis demonstrates that the increase in sialic acid is associated with increased production and/or sialylation of components with MW of 45–60 kDa.
• 4.4. A high percentage (64%) of the sialic acid in newborn calf serum is detected with the lipid-linked sialic acid assay, relative to 20 day old (25%) or mature (18%) animals.
• 5.5. This indicates that the glycoproteins of newborn calf serum are more efficiently extracted under the conditions of this assay than glycoproteins of mature serum.

     

Time related changes in the free amino acid pool of the sea anemone,Bunodosoma cavernata,during salinity stress

• 1.1. The sea anemone, Bunodosoma cavernata, is a relatively eurybaline cnidarian tolerating salinities from 12 to 40%.
• 2.2. Taurine, glutamic acid and aspartic acid all showed some increases with increased salinity.
• 3.3. The amino acid showing the greatest accumulation under high salinity conditions was β-alanine which increased 28-fold from 1.5 to 41.9 μmol/g dry weight when salinity was raised from 26 to 40%.
• 4.4. When B. cavernata was subjected to increased salinity, β-alanine was rapidly accumulated and reached maximum levels within 4 days.
• 5.5. When salinity was dropped from 36 to 26%0, β-alanine concentrations dropped from 15 to 2 μmol/g dry weight in 2 days.

     

Accumulation,distribution and toxicity of selenium in the adult house fly,Musca domestica

• 1.1. Accumulation and distribution of dietary Se in relation to mortality was investigated in adult house flies.
• 2.2. The midgut preferentially accumulated Se and thereby limited toxicity.
• 3.3. Midgut Se concentrations were from 6- to 107-fold higher than in carcass, and from 15 to 71% of the total Se was associated with midgut.
• 4.4. When dietary levels of Se were raised the midgut saturated at 15 μg Se/g tissue, followed by a rise in carcass levels to greater than 0.5 μg Se/g tissue and increased mortality.
• 5.5. Se levels in lysosomal fractions were from 3- to 50-fold higher than in other subcellular fractions, suggesting that Se is sequestered in lysosomes.
• 6.6. Se added to drinking water was toxic at 4–8 ppm.

     

Characteristics of Crassostrea virginica crystalline style chitin digestion

• 1.1. Fundamental chitin digestion characteristics of Crassostrea virginica crystalline style were investigated.
• 2.2. Optimum temperature and pH were 34°C and 4.8. respectively.
• 3.3. The colloidal regenerated chitin (0.56mol/0.5 ml: GlcNAc equivalents) was saturating under all enzyme levels encountered.
• 4.4. There was no evidence of end product inhibition, even after 100 hr incubation.
• 5.5. Calculated K_m for the chitinase complex was 1.19mM when determined using a 30 min assay, but was only 0.70 mM when determined using a 4.6 hr assay.
• 6.6. Both K_m values are lower than reported for similar assays in other molluscs and for most bacteria.
• 7.7. Effect of substrate preparation on the kinetics are discussed.
• 8.8. Eight peaks of chitinase activity were resolved by DEAE-Fractogel ion exchange chromatography.

     

Anuran amphibia which are not acclimable to high salt,tolerate high plasma urea

• 1.1. The capacity of five anuran Amphibians (Bufo viridis B. regularis, Rana ridibunda, Hyla arborea and Pelobates syriacus) to acclimate to NaCl and urea solutions was investigated.
• 2.2. All species could be acclimated to relatively high concentrations of urea solutions, while only Bufo viridis and Hyla arborea could be acclimated to 500 mOsm/kg or higher NaCl solutions.
• 3.3. The plasma urea concentration in B. viridis and H. arborea was elevated to levels over 140 mmol/1.
• 4.4. The sum of plasma sodium and chloride concentrations did not increase over 400 mmol/l in any species.
• 5.5. Urine osmolality, which was normally low, increased, but never exceeded the plasma osmolality.
• 6.6. In the urea acclimation conditions, urine electrolytes diminished, similarly in all species in this study.
• 7.7. It is concluded that anuran Amphibians can tolerate high plasma urea concentrations, but only those species which can elevate it, either through retention or net synthesis, can be acclimated to high salt solutions.

     

Combined effect of adenosine,alpha adrenergic and adenosine antagonists on serum insulin and insulin secretion from rat pancreatic islets

• 1.1. The effect of adenosine separately or in combination with alpha-1 adrenergic antagonist prazosin and alpha-2 adrenergic antagonist yohimbine as well as adenosine antagonists 8-phenyltheophylline and xanthine amine conjugate on glucose-induced insulin secretion from isolated rat pancreatic islets was studied.
• 2.2. Their in vivo effects on serum glucose and insulin levels were also investigated. Adenosine at 10 and 100 μM inhibited significantly, insulin secretion from the isolated islets whereas at 10 mM slightly increased the secretion of insulin.
• 3.3. Prazosin used at 100 μM inhibited insulin secretion. When it combined with adenosine (10 μM) it augmented the inhibitory effect of adenosine.
• 4.4. In vivo prazosin (21 mg/kg bodywt) caused a hyperglycaemia which was accompanied by hypoinsulinaemia.
• 5.5. Concurrent administration of this drug with adenosine neither affect the hyperglycaemic nor the hypoinsulinaemic effects of adenosine.
• 6.6. On the other hand, yohimbine (100 μM) has no effect neither separately nor in combination with adenosine (10 μM) in modulating the inhibitory effect of adenosine on insulin secretion.
• 7.7. When Yohimbine administered at 19.5 mg/kg body wt it did not alter serum glucose but it markedly increased the serum insulin level. Its combined administration with adenosine reduced the hyperglycaemic effect of adenosine with a remarkable increase in serum insulin.
• 8.8. Both adenosine-antagonists were ineffective in alteration of insulin secretion.
• 9.9. However, combination of 8-phenyltheophylline with adenosine (10 μM) totally blocked the inhibitory effect of adenosine on insulin secretion while xanthine amine conjugate failed to prevent this effect of adenosine.
• 10.10. These results indicate that the inhibitory effect of adenosine on insulin secretion is neither mediated via alpha-1 nor alpha-2 adrenoceptors. It might be via activation of specific adenosine receptors on rat islets which are sensitive to blockade by 8-phenyltheophylline.

     

Sodium balance in adult atlantic salmon (Salmo salar L.) during migration into neutral and acid fresh water

• 1.1. In sea-water, adult salmon (S. salar) exchange an average of 12.6% of total body sodium/hr.
• 2.2. Following transfer to fresh water sodium uptake follows Michaelis-Menton kinetics. F_max = 2.40 mmol Na/1 ECF/hr, K_m = 0.26 mmol Na/1. The uptake system is fully activated immediately following transfer to fresh water.
• 3.3. Post smolts adapted to sea-water for 3 months take up sodium at only one third of the rate of adult fish following return to fresh water.
• 4.4. The concentration of prolactin in the plasma is low in sea-water adapted fish and does not rise during the first 8 hr in fresh water.
• 5.5. At pH 5 sodium uptake is reduced by almost 90%, even in the absence of aluminium, but recovers immediately on return to neutral water.
• 6.6. At pH 5 and 20 μmol Al/1 there is little further effect on sodium uptake but after 6 hr in aluminium the inhibition of sodium uptake continues after return to neutral aluminium fresh water and uptake is only 50% of normal 24 hr later.

     

Biochemical aspects of Balanus hameri haemolymph,together with some comparative haemolymph data for Balanus balanus and Lepas anatifera

• 1.1. The concentration of protein in the haemolymph of Balanus hameri ranged from 2.0 to 17.3 mg/ml, and the lipid from 1.4 to 7.7 mg/ml; the haemolymph protein and lipid levels increased significantly prior to cross-fertilization.
• 2.2. The protein and lipid concentrations in Balanus balanus haemolymph were 8.1 and 1.7 mg/ml respectively.
• 3.3. The lipid concentration of Lepas anatifera haemolymph was 1.2 mg/ml.
• 4.4. The neutral lipid and phospholipid components of B. hameri and L. anatifera haemolymph were the same, with the major components of the phospholipid fraction being phosphatidyl ethanolamine and phosphatidyl choline.
• 5.5. The osmolarity (970.4 mOsm), chloride ion concentration (501.3 m-eq/l) and pH (7.29) of B. hameri haemolymph were also determined.

     

Miniature gel filtration: a simple and inexpensive method for the measurement of protein- and non-protein-bound cortisol: application to guinea pig plasma

• 1.1. A method is described for the accurate and rapid measurement of protein- and non-protein-bound cortisol by miniature gel filtration in small volumes of plasma, e.g. of rodents.
• 2.2. Binding of cortisol by guinea pig plasma proteins is strongly reduced at elevated temperature (4°C: 102 ± 12ng/ml; 40°C: 5 ± 2 ng/ml).
• 3.3. Incubation of guinea pig plasma with 1–5000 ng cortisol resulted in a dose-dependent increase in cortisol bound to proteins (specific binding by corticosteroid binding globulin: 230 ± 12 ng/ml).
• 4.4. Administration of 20 IU (1–24)ACTH induced a significant increase of total protein-bound and non-protein-bound cortisol.
• 5.5. Values reported in this study agree well with those of previous investigations, in which bound and non-bound glucocorticosteroids were separated by gel filtration on large Sephadex® columns.

     

Histochemical staining of cadmium taken up by the midge larva,Chironomus yoshimatsui (diptera,chironomidae)

• 1.1. The midge larva (Chironomus yoshimatsui) exposed to cadmium (10 μg Cd/ml) for 2 days was histochemically stained with benzothiazolylazo-β-naphthol.
• 2.2. A large portion of cadmium taken up by the larvae was distributed to the digestive tract, epithelial tract and fat bodies.
• 3.3. Cadmium accumulated in the fat bodies was discharged slowly relative to cadmium in the tract contents when the larvae were placed in control water.
• 4.4. Glycogen in the fat bodies of cadmium-exposed larvae was insensitive to PAS staining.

     

Characteristics of the in vitro assembly of brain tubulin of Cyprinus carpio

• 1.1. Tubulin has been isolated from brain of carp (Cyprinus carpio), acclimated to summer temperatures (16–20°C), and its in vitro reassembly behavior has been characterized.
• 2.2. Among the striking properties of this tubulin preparation is the temperature profile showing a high level of polymerization at the environmental temperature of carp.
• 3.3. The critical tubulin concentration for assembly was 0.8 mg/ml, which was higher than mammalian tubulin purified by the cycle procedure.
• 4.4. The microtubular protein showed three high mol.wt component and a minor component of about 43,000 daltons was also found to copurify with tubulin.

     

Seasonal variation of LH and testosterone in the smallest deer,the pudu (Pudu puda molina) and its relationship to the antler cycle

• 1.1. In order to obtain a seasonal profile of LH, three adult male pudu (Pudu puda, Molina) were sampled monthly from the saphenous vein for a period of one year.
• 2.2. A significant circannual variation of plasma LH levels was detected with an average peak value (1.77 ng/ml) recorded in February and nadir concentrations (0.19 ng/ml) observed in November.
• 3.3. The peak level of testosterone (1.54 ng/ml) was detected in March, the time of the rut.

     

The inhibitory effect of tetramethylethylene diamine on water soluble and membrane bound acetylcholinesterase activity

• 1.1. The inhibitory effect of N,N,N′,N′-tetramethylethylene diamine (TEMED) on water soluble (WSAChE) and membrane bound (MBAChE) acetylcholinesterase was investigated.
• 2.2. TEMED (0.5–4.0 mM) reversibly inhibited WSAChE activity (18–62%) and MBAChE (20–61%) in a concentration dependent manner.
• 3.3. The IC₅₀ being about 2.8 mM for WSAChE and 2.6 mM for MBAChE.
• 4.4. Lineweaver-Burk plots indicated that the nature of inhibition is noncompetitive for both water soluble and membrane bound acetylcholinesterase, with K_m values 68 μM and 123 μM respectively.
• 5.5. An Arrhenius plot showed that the transition temperature (TT) is unaffected in the presence of TEMED.
• 6.6. The activation energy was increased below and above TT in the case of WSAChE only.
• 7.7. On the basis of this behaviour of TEMED with AChE. it can be proposed that it can be used as an eluting agent for the bounded AChE to affinity ligand and may have beneficial action on the reactivatability of irreversibly-inhibited AChE due to its structure.
• 8.8. Moreover there is a possibility that it can be used as a therapeutic agent for the treatment of Alzheimer's disease, myasthenia gravia and glaucoma like some other inhibitors of AChE.