Isolation and partial characterization of a second myotropic peptide from the hindgut of the cockroach,Leucophaea maderae

• 1.1. Proctolin and a second myotropic peptide were extracted from the hindgut of the cockroach Leucophaea maderae with methanol-water-acetic acid (90:9:1). The two peptides were easily separated by HPLC on a μ-Bondapak-phenyl column.
• 2.2. Like proctolin, the second peptide was heat stable and was inactivated by the exopeptidases aminopeptidase M and carboxypeptidase Y.
• 3.3. The response of the isolated hindgut to the new peptide was distinguishable from the response to proctolin by the following features: (a) a longer interval following application (1–4 min) to reach a maximum contraction, and (b) a much larger amplitude for single phasic contractions. Like proctolin, the new peptide could cause a protracted stimulation of the hindgut for more than 2 hr.

     

Alteration of the protein composition of bothrops jararaca venom and venom gland by isoproterenol treatment

• 1.1. The protein composition of Bothrops jararaca venom and venom gland was analyzed through SDS-PAGE, after isoproterenol (IPR) treatment.
• 2.2. Some proteins (47, 48, 57 and 72 kDa) were detected in the gland homogenate from the control but not from the IPR-treated samples.
• 3.3. Three proteins (26.5, 44.5 and 53 kDa) were detected in the venom gland from IPR-treated snakes but not from the venom gland from the control.
• 4.4. In the venom samples proteins of 41 and 74 kDa were detected only in the IPR treated samples, while proteins of 17 and 28 kDa were detected only in the control.
• 5.5. The biological activity of the venom did not change with IPR treatment.

     

The multiplicity of neurotransmitters and neurohormones controlling mytilus muscle

• 1.1. The effects of various biogenic amines on contractions of the ABRM of M. edulis in response to repetitive electrical stimulation, ACh and high K⁺ concentration were examined.
• 2.2. Octopamine, serotonin, dopamine, noradrenaline, tyramine and phenylethanolamine potentiated the contractions of ABRM. Octopamine was found to be the most potent. Histamine did not potentiate.
• 3.3. Phentolamine blocked the potentiating action of octopamine and noradrenaline and partially blocked dopamine, but it did not block serotonin. Phentolamine also blocked the potentiating after-effect of repetitive electrical stimulation on subsequent contractions. It is suggested that octopamine is a neurotransmitter or a local neurohormone which potentiates contraction of the ABRM.
• 4.4. Under certain conditions, high concentrations of dopamine and serotonin inhibited contractions in response to ACh and high K⁺ concentration. Thus, these amines have not only potentiating but also inhibitory action on contraction of the ABRM, in addition to relaxing catch.
• 5.5. It is suggested that a wide spectrum of substances participates in the physiological control of contractility in the ABRM.

     

A comparative study on the biological properties of venoms from juvenile and adult common tiger snake (Notechis scutatus) venoms

• 1.1. The biological properties of venoms from juvenile and adult common tiger snakes (Notechis scutatus) were compared.
• 2.2. The lethality, procoagulant activity and enzymatic activities of the juvenile venom were not substantially different from those of the adult venom.
• 3.3. Electrophoretic studies, however, indicated some minor differences in the protein composition of the juvenile and adult venoms.

     

Acid and alkaline phosphomonoesterase activities in snake venoms

• 1.1. Acid and alkaline phosphatase activities of eight different snake venoms were determined quantitatively by using synthetic substrates, o-carboxyphenylphosphate and p-nitrophenylphosphate respectively.
• 2.2. It was found that most of Elapidae venoms investigated had both acid and alkaline phosphatase activities.
• 3.3. Three Crotalidae venoms investigated did not show any alkaline phosphatase activity.
• 4.4. The strength of venom acid phosphatase activity is as follows: Agkistroden acutus > Naja haje > Naja naja samarensis > Naja naja atra > Naja melanoleuca.
• 5.5. The strength of venom alkaline phosphatase activity by using p-nitrophenylphosphate is in the order of Naja hannah > Naja haje > Naja naja samarensis > Naja naja atra > Naja melanoleuca.When o-carboxyphenylphosphate was used as a substrate, the order of enzyme activity is Naja hannah > Naja haje > Naja naja samarensis > Naja melanoleuca > Naja naja atra.
• 6.6. Acid phosphatase activity of all the Elapidae venoms was inhibited completely by fluoride. The alkaline phosphatase activity of Elapidae venoms was not inhibited by fluoride either using p-nitrophenylphosphate or o-carboxyphenylphosphate.
• 7.7. The acid phosphatase of all the Elapidae venoms was not inhibited by zinc ion. However, most of the venom alkaline phosphatases were inhibited by zinc ion.
• 8.8. Ethylenediaminetetraacetic acid (EDTA) had inhibitory action on venom phosphatase activity. However, tris-(hydroxymethyl)-aminoethane had a counter effect on the inhibitory action of EDTA.
• 9.9. Optimum pH studies of the snake venom phosphatases showed that the acid phosphatases of the snake venoms had their highest activity in the range of pH 4–5. The alkaline phosphatases of the snake venoms had their optimum pH at 9.
• 10.10. Comparable experiments were also conducted by using chicken intestine alkaline phosphatase and wheat germ acid phosphatase.

     

Effect of lindane on phosphatidylinositol synthesis by cerebral cortex after acute and subchronic treatment

• 1.1. The incorporation of myo-[2-³H]inositol into phosphatidylinositols was unmodified in brain cortex miniprisms from convulsant rats.
• 2.2. However, the incorporation had increased by 300–400% in non convulsant rats which had received the same amount of lindane at a lower concentration.
• 3.3. This result suggests that phosphatidylinositols are implicated in the convulsion syndrome.
• 4.4. Experiments with lindane added in vitro were performed with both subchronically lindane intoxicated and untreated rats.
• 5.5. The results show an interesting lack of parallelism.
• 6.6. This might indicate the development of some resistance to the effects of lindane, possibly as the result of complex compensatory changes in inositol lipid biosynthesis.

     

Carbohydrate transport in polychaeta: Reabsorption and accumulation of maltose by the nephridia of Sabella pavonina S

• 1.1. The glucose and maltose concentrations measured in the thoracic coelomic fluid of Sabella were respectively 0.05 and 0.15mg/ml.
• 2.2. Maltose transport was observed to be carrier-mediated in the nephridial wall, with a V_max of 0.03 nmol/min and a K_m of 0.24 mmol/l.
• 3.3. The accumulation rate of maltose in the nephridia was proportional to its reabsorption rate, and exhibited no plateau.

     

Hemorrhagic and mojave toxins in the venoms of the offspring of two mojave rattlesnakes (Crotalus scutulatus scutulatus)

• 1.1. The venoms of two Mojave rattlesnakes and those of their offsprings were analyzed for Mojave toxin and hemorrhagic toxin.
• 2.2. The venom of one female, collected in Pima County, Arizona, and the venoms of her six offspring contained hemorrhagic toxin but not Mojave toxin (venom B).
• 3.3. The venom of the second female, captured in El Paso County, Texas, contained both toxins (A + B venom). Of her 10 offspring, five contained venom with both toxins, two had hemorrhagic toxin only, and three contained neither toxin.
• 4.4. Venoms that caused hemorrhage also inactivated complement. A pool of the venoms of the venom B offspring was less toxic than adult pooled venom A.

     

Changes in the concentration of some minor constituents of milk from cows fed low- or high-fat diets

• 1.1. The concentration of isocitrate and 2-oxoglutarate in cows' milk was determined in cows fed low- or high-fat diets.
• 2.2. The concentration of 2-oxoglutarate in milk correlated positively with the short and medium chain fatty acids in milk fat.
• 3.3. The concentration of isocitrate in milk correlated negatively with the short and medium chain fatty acids in milk fat.
• 4.4. It is proposed that changes in the concentrations of these minor constituents of milk occur as a result of changes in their intracellular concentrations. In the present experiment these changes are probably the result of changes in the rate of fatty acid synthesis de novo in the mammary gland.

     

Isolation of a hemorrhagic toxin from the venom of Agkistrodon contortrix laticinctus (broad-banded copperhead) and pathogenesis of the hemorrhage induced by the toxin in mice

• 1.1. A hemorrhagic toxin was isolated from the venom of Agkistrodon contortrix laticinctus (Broad-Banded Copperhead) by Sephacryl S-200 HR column chromatography followed by high performance chromatography on Waters DEAE 5PW and protein Pak 125 columns.
• 2.2. Homogeneity was determined by the presence of a single band in acrylamide gel electrophoresis with silver staining.
• 3.3. ACL hemorrhagic toxin I has a molecular weight of about 29,000, is slightly acidic, and is a metalloprotease with activity towards the substrates N,N-dimethylcasein and bovine fibrinogen. Although the toxin is able to hydrolyze fibrinogen in vitro, it does not possess any defibrinogenating activity in vivo whereas the crude venom does show this activity. It has similar cleavage specificities to other snake venom hemorrhagic toxins.
• 4.4. ACL hemorrhagic toxin I causes hemorrhage of rapid onset, present within 5 min of intramuscular injection into mice, and the pathogenesis is one of hemorrhage per rhexis in which capillary endothelial cells are ruptured.

     

Calcium binding by sarcoplasmic reticulum and mitochondria isolated from an annelid visceral muscle in relation to whole muscle calcium influx and efflux

• 1.1. Nereis pharangeal visceral muscle is composed of obliquely striated fibres with low mitochondrial density and moderately developed sarcoplasmic reticulum.
• 2.2. Isolated mitochondria and sarcoplasmic reticulum showed moderate passive calcium binding but only low ATP-promoted calcium binding which was inhibited by caffeine.
• 3.3. Whole fibres preloaded with Ca⁴⁵ showed a two compartment efflux. The slow, presumably intracellular, compartment accounted for only 10% of total Ca⁴⁵ activity.
• 4.4. Both acetylcholine and high KCl treatments stimulated calcium influx, causing contractures while calcium-free and EGTA treatments inhibited both these contractures and normal spontaneous contractions.
• 5.5. Lanthanum inhibited normal contractility and KCl contractures. Lanthanum also inhibited Ca⁴⁵ influx but was without effect on Ca⁴⁵ efflux.
• 6.6. It is concluded that there is little calcium storage capacity in these visceral muscle fibres and that normal contractions are strongly dependent upon extracellular calcium influx.

     

Cardiac responses of the anurans,Bufo bufo and Rana pipiens,during behavioural arousal and fright

• 1.1. Electrocardiograms (ECGs) were recorded from B. bufo and R. pipiens whilst behaviourally aroused and frightened.
• 2.2. A tachycardia was exhibited in both states, though in fright it was preceded by a “missed” beat.
• 3.3. The difference between these responses and those of other vertebrates was discussed in relation to the amphibious habit.
• 4.4. It is suggested that the cardiac responses of diving, fright and arousal may have a common evolutionary origin.

     

A comparative study of clothing factors from the venom of Agkistrodon acutus collected in China and Taiwan

• 1.1. Two clotting factors, Cf-1(C) and Cf-2(C) were isolated from Agkistrodon acutus (collected in China) venom by gel filtration, ion-exchange chromatography and affinity chromatography. Using the same procedure, two clotting factors, Cf-1(T) and Cf-2(T), were isolated from Agkistrodon acutus (collected in Taiwan) venom and their characteristics were compared with Cf-1(C) and Cf-2(C).
• 2.2. Molecular weights of Cf-1(C), Cf-2(C), Cf-1(T) and Cf-2(T) were determined to be 44,000, 70,000, 25,000 and 44,000 respectively. The factors were not immunologically related.
• 3.3. The four clotting factors possessed tosyl-l-arginine methyl ester (TAME) hydrolyzing activity and coagulated fibrinogen to fibrin. Only Aα chain was cleaved when fibrinogen was incubated with each factor.
• 4.4. Agkistrodon acutus is not classified by geographical location, however it is obvious that venom components vary between the Chinese and Taiwanese forms.

     

Effects of K+, Ba2+ and Ca2+ on the excitable membrane in Paramecium tetraurelia

• 1.1. The effects of Ba²⁺ and K⁺ ions on the membrane currents of Paramecium tetraurelia under a voltage clamp were investigated.
• 2.2. External Ba²⁺ suppresses the inward-going K-current and the Ca-induced K-outward current and changes the activation and inactivation kinetics of transient inward current through the Ca-channel.
• 3.3. K⁺ increases the Ca-induced K-conductances but little affects the leakage conductance.
• 4.4. The resting potentials by changing those ionic concentrations shift the voltage sensitivities of all voltage sensitive channels, simultaneously.
• 5.5. The competition between ions to the channel responses was discussed.

     

Isolation and characterization of phospholipase A2, from Agkistrodon bilineatus (common cantil) venom

• 1.1. Phospholipase A₂ was isolated from Agkistrodon bilineatus venom by Sephadex G-75 and CM-Cellulose column chromatographies.
• 2.2. The purified phospholipase A₂-I gave a single band on disc polyacrylamide gel electrophoresis, isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis.
• 3.3. The enzyme preparation had a molecular weight of 14,000, isoelectric point of pH 8.77 and possessed 123 amino acid residues.
• 4.4. The purified phospholipase A₂ possessed lethal, indirect hemolytic and anticoagulant activities.
• 5.5. The enzyme hydrolyzed the phospholipids phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI) and phosphatidyl serine (PS).
• 6.6. The concentration of mouse diaphragm was inhibited and the contraction of guinea pig left atrium was increased by phospholipase A₂-I.
• 7.7. Phospholipase A₂ activity of this preparation was inhibited by ethylenediamine tetraacetic acid, p-bromo phenacyl bromide, n-bromo succinimide or dithiothreitol, but not by diisopropyl fluorophosphate or benzamidine.

     

Conodipine-P1-3, the First Phospholipases A2 Characterized from Injected Cone Snail Venom*

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Highlights

• •Three novel Conodipines P1-3 in the injected venom of Conus purpurascens.
• •Conodipines P1-3 have consensus catalytic characteristics of sPLA₂.
• •We determined multiple modification sites in Conodipines P1-3.
• •Evaluated the activity of Conohyal-P1 by a MS-based method.

     

Purification and some properties of an atypical alkaline p-nitrophenylphosphate phosphatase activity from Halobacterium halobium

• 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
• 2.2. The enzyme has an apparent molecular weight of 24,000.
• 3.3. A K_m value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
• 4.4. The enzyme is selectively activated and stabilized by Mn²⁺.
• 5.5. It requires high salt concentrations for stability and maximum activity.
• 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.

     

Measurements of oxygen consumption in Mytilus edulis during exposure to,and recovery from,high sublethal concentrations of formaldehyde,benzene and phenol

• 1.1. The rate of oxygen consumption has been monitored continuously in M. edulis during acute exposure to high sublethal concentrations of formaldehyde, phenol and benzene and subsequent recovery periods of 96 hr.
• 2.2. The results are discussed in relation to changes in the electrochemical potential difference of sodium, the content of ATP and the tissue concentration of strombine.
• 3.3. After exposure to benzene and phenol, an increase in the rate of oxygen consumption that could not be explained by oxygen debt from the exposure period was observed.
• 4.4. Depression of the rate of oxygen consumption after exposure to formaldehyde may be explained by a reduced ability to extract oxygen from the water.
• 5.5. The pattern of oxygen consumption and behavioural responses, as well as the combined changes in the biochemical markers, were distinctly different in the three cases.

     

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.