Acclimatory responses in enzymatic activity and metabolite concentrations in the tropical scorpion Heterometrus fulvipes

1. 1.|Changes in tissue metabolite concentrations and enzyme activities in the pedipalpal (PM) and heart (HM) muscles of the tropical scorpion Heterometrus fulvipes show that the metabolism in PM and HM is fundamentally reorganized following low (18°C) and high (38°C) temperature acclimation.

2. 2.|Changes in metabolite concentrations show that metabolite biosynthesis showed increases after cold acclimation but decreases after warm acclimation.

3. 3.|Similarly, changes in enzyme activities show a preponderance of glycolysis and HMP shunt activity after cold acclimation, while after warm acclimation glycogenolysis, oxidative metabolism and gluconeogenesis predominated.

4. 4.|Higher metabolite concentrations and enzyme activities both before and after thermal acclimation in HM reflect its greater compensatory abilities.

Pharmacology of insect GABA receptors

A GABA-operated Cl^– channel that is bicuculline-insensitive is abundant in the nervous tissue of cockroach, in housefly head preparations and thorax/abdomen preparations, and in similar preparations from several insect species. Bicuculline-insensitive GABA-operated Cl^– channels, which are rare in vertebrates, possess sites of action of benzodiazepines, steroids and insecticides that are pharmacologically-distinct from corresponding sites on vertebrate GABA_A receptors. The pharmacological profile of the benzodiazepine-binding site linked to an insect CNS GABA-operated Cl^– channel resembles more closely that of vertebrate peripheral benzodiazepine-binding sites. Six pregnane steroids and certain polychlorocycloalkane insecticides, which are active att-butylbicy-clophosphorothionate (TBPS)-binding sites, also differ in their effectiveness on vertebrate and insect GABA receptors. Radioligand binding and physiological studies indicate that in insects there may be subtypes of the GABA receptor. Molecular biology offers experimental approaches to understanding the basis of this diversity.Special issue dedicated to Dr. Eugene Roberts     

Respiration Rate of Steinernema feltiae Infective Juveniles at Several Constant Temperatures

Respiration was measured in dauer stages of the insect-parasitic nematode Steinernema feltiae (= Neoaplectana carpocapsae) at 7, 17, and 27 C. Respiration, Q₁₀, and nematode viability were temperature dependent. Mean O₂ consumption for 5 × 10⁵ nematodes the first 24 hours was 0.27 ml at 7 C, 0.83 ml at 17 C, and 2.68 ml at 27 C. The Q₁₀ was 3.10 for 7-17 C and 3.24 for 17-27 C. Some nematodes died during 2, 14, and 21 days at 27, 17, and 7 C, respectively. The respiratory quotient was below 1 at all temperatures tested. A standard asymptotic model is expressed as oxygen consumed = 2.77 * {1 - exponent[-time * exponent(-B + C * temperature)]}; where 2.77 is the maximum response at 27 C. This model estimates nematode O₂ consumption and viability at storage temperatures between 7 and 27 C. The nematodes died when the O₂ concentration reached 0.5 ml/5 × 10⁵ nematodes. This model may be used to predict O₂ requirements of S. feltiae infective juveniles when stored as a waterless concentrate.     

Nippostrongylus brasiliensis: feeding activity in the mouse

Nippostrongylus brasiliensis incorporated the fluorescent dye, Rhodamine B, while feeding in vivo. Uptake of dye in both sexes of helminth increased linearly from 30 to 120 min after the hosts were given dye per os. Feeding by female N. brasiliensis significantly exceeded that of the male at 4 and 5 days postinfection. Feeding declined in older helminths of both sexes. The density of helminths had no effect on their incorporation of dye in vivo. Feeding in male- and female-only groups of worms was similar to that seen in populations of mixed sexes. Feeding by helminths decreased during the first 36 h of food deprivation in the host, but increased during subsequent fasting of the host. Both sexes of N. brasiliensis resumed feeding within 15 min after the fasted hosts were fed. Growth of N. brasiliensis increased linearly from 4 to 7 days postinfection, based on dry weight. Seven-day-old and older females were significantly heavier than males.     

Demonstration of a beta-casomorphin immunoreactive material in the plasma of newborn calves after milk intake

Blood was collected from newborn calves before and after their first milk intake after birth; extracts of plasma were assayed by radioimmunoassay for the presence of beta-casomorphin-7 immunoreactive materials. No beta-casomorphin immunoreactivity was found in samples collected before milk ingestion; however, in samples collected after milk ingestion a beta-casomorphin-7 immunoreactive material was detected. Chromatographic characterization showed that this material was not identical with beta-casomorphin-7 but might rather represent a precursor thereof. The material proved resistant to enzymatic attack during a 30-min incubation period at 37 degrees C in the plasma of newborn calves, whereas beta-casomorphin-7 was degraded under these conditions. A physiological significance of beta-casomorphin-7 eventually cleaved from such a precursor material at any site in the newborn mammal is suggested.     

The primary structure of hemoglobin from amur-leopard (Panthera pardus orientalis)

The complete amino acid sequence of the major component of hemoglobin from amur-leopard (Panthera pardus orientalis) is presented. The major component accounts for more than 90% of the total hemoglobin. Separation of the globin subunits was achieved by ion-exchange chromatography on CM-cellulose in urea. The sequence was studied by automatic Edman degradation of tryptic and hydrolytic peptides. Alignment was carried out with human hemoglobin sequence. The NH₂ terminus is blocked with Ac-serine. The data are compared with other mammalian hemoglobins and results are discussed with respect to sequence and physiology.85th communication on hemoglobin.     

Thermophilic anaerobic spirochetes in New Zealand hot springs

Abstract Electron and light microscopy revealed the presence of spirochetes in New Zealand thermal springs. The spirochete population in one spring studied (Kuirau Lake) was affected by fluctuations in temperature and/or pool level. A pure culture of the strictly anaerobic bacterium revealed that it grew optimally at a temperature of 45–50°C, with no growth occurring above 60°C, and a pH of 7.0–7.5 with no growth occurring at pH 5.5 or 8.5. Growth was inhibited by chloramphenicol, penicillin, streptomycin, tetracycline and neomycin but not by d -cycloserine, novobiocin or phosphomycin at 10 μg/ml. A wide range of carbohydrates were utilized but not organic acids. Acetate was the major end product of glucose fermentation with substantial amounts of ethanol and traces of lactate being produced.     

Interrelationships between Ethylene Production,Gall Formation,and Root-knot Nematode Development in Tomato Plants Infected with Meloidogyne javanica

Ethylene production was determined in excised tomato (Lycopersicon esculentum) root cultures of Meloidogyne javanica susceptible and resistant cultivars infected with M. javanica. Uninfected cultivars produced very low amounts of ethylene. Relatively high amounts of ethylene were produced by the infected susceptible cultivars. Peak production of 1.6 n moles * g root⁻¹ * h¹⁻ occurred between 9 and 16 days after inoculation (DAI). The period of high ethylene production coincided with that of rapid increase in gall weight. Low amounts of ethylene were also released by the infected resistant cultivar between 9 and 12 DAI, which follows the hypersensitivity reaction. Ethylene production in infected intact plants during the period of rapid gall growth was twice as much as in uninfected plants during the same time. Exposing excised root cultures to 0.5 or l0 ppm ethylene accelerated the rate of increase in gall weight of M. javanica infected roots. In contrast, overall root growth was inhibited by these treatments, compared to infected roots which were not exposed to ethylene.     

The efficacy of biobehavioral and compliance interventions in the adjunctive treatment of mild pregnancy-induced hypertension

This investigation assessed the efficacy of a biobehavioral intervention in the adjunctive treatment of mild pregnancy-induced hypertension (PIH), a potentially serious complication of pregnancy in which normotensive women develop hypertension, proteinuria, and edema of unknown etiology late in gestation. Forty-five women with symptoms of PIH were randomly assigned to one of three treatment conditions: bed rest alone (the most common obstetrical treatment), bed rest with individualized compliance enhancement training, or a four-session biobehavioral treatment consisting of bed rest, compliance enhancement training, and individualized thermal biofeedback-assisted relaxation training. Results indicated that while blood pressure for the bed rest and compliance enhancement groups continued to rise and pose an increasing health risk to maternal and fetal well-being, subjects in the biobehavioral group maintained their blood pressure at a significantly lower, and presumably safer, level. The biobehavioral treatment is hypothesized to affect blood pressure levels in subjects with mild PIH through the mediation of the sympathetic nervous system, decreasing peripheral vascular resistance and cardiac output. The results of this investigation suggest that the biobehavioral intervention may be an effective adjunct to bed rest in the treatment of mild PIH remote from term.