Anxiety-related defensive behavioral responses in mice selectively bred for High and Low Activity

High and Low Activity strains of mice (displaying low and high anxiety-like behavior, respectively) with 7.8–20 fold differences in open-field activity were selected and subsequently inbred to use as a genetic model for studying anxiety-like behavior in mice (DeFries et al., 1978, Behavior Genetics, 8:3-13). These strains exhibited differences in other anxiety-related behaviors as assessed using the light–dark box, elevated plus-maze, mirror chamber, and elevated square-maze tests (Henderson et al., 2004, Behavior Genetics, 34: 267-293). The purpose of these experiments was three-fold. First, we repeated a 6-day behavioral battery using updated equipment and software to confirm the extreme differences in anxiety-like behaviors. Second, we tested novel object exploration, a measure of anxiety-like behavior that does not rely heavily on locomotion. Third, we conducted a home cage wheel running experiment to determine whether these strains differ in locomotor activity in a familiar, home cage environment. Our behavioral test battery confirmed extreme differences in multiple measures of anxiety-like behaviors. Furthermore, the novel object test demonstrated that the High Activity mice exhibited decreased anxiety-like behaviors (increased nose pokes) compared to Low Activity mice. Finally, male Low Activity mice ran nearly twice as far each day on running wheels compared to High Activity mice, while female High and Low Activity mice did not differ in wheel running. These results support the idea that the behavioral differences between High and Low Activity mice are likely to be due to anxiety-related factors and not simply generalized differences in locomotor activity.     

Activity ratios of ribulose-1,5-bisphosphate carboxylase accurately reflect carbamylation ratios

Activity ratios and carbamylation ratios of ribulose-1,5-bisphosphate carboxylase (RuBPCase) were determined for leaves of Phaseolus vulgaris and Spinacia oleracea exposed to a variety of partial pressures of CO₂ and O₂ and photon flux densities (PFD). It was found that activity ratios accurately predicted carbamylation ratios except in extracts from leaves held in low PFD. In particular, it was confirmed that the loss of RuBPCase activity in low partial pressure of O₂ and high PFD results from reduced carbamylation. Activity ratios of RuBPCase were lower than carbamylation ratios for Phaseolus leaves sampled in low PFD, presumably because of the presence of 2-carboxyarabinitol 1-phosphate. Spinacia leaves sampled in darkness also exhibited lower activity ratios than carbamylation ratios indicating that this species may also have an RuBPCase inhibitor even though carboxyarabinitol 1-phosphate has not been detected in this species in the past.     

The genetics of behavior

A review of the papers published in the Journal of Higher Nervous Activity dedicated to behavioral and neurophysiological studies carried out using the genetic approach is presented. The review is based on classification, which subdivides the diversity of behavioral phenomena into three large categories: instinctive, acquired behavior, and elementary reasoning phenomena. The main contribution to these publications was made by researches at the Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch (Novosibirsk), Institute of Physiology, Russian Academy of Sciences (St.-Petersburg), and Department of Physiology of Higher Nervous Activity, Biological Faculty, Lomonosov State University (Moscow). The traditional lines of investigations are: behavioral and neurochemical consequences of domestication, numerous physiological correlations in rat strains selected for high and low excitability levels, and genetic studies of animal reasoning.     

Background activity pattern of guinea pig septal neurons in vitro

Activity of medial septum-diagonal band cells (MS-DB neurons) was investigated in slices of guinea pig septum. Four types of activity were distinguished on the basis of interspike interval distribution and coefficient of variation (CV): extremely regular (CV<0.3), regular (CV>0.3<0.7), irregular (CV>0.7), and rhythmic bursting patterns. Activity of cells belonging to the first group was resistant to superfusion with a medium low in Ca²⁺ and high in Mg²⁺ which produces blockade of synaptic effects. The same applied to a percentage of neurons with a rhythmic bursting pattern. Activity pattern of Mg²⁺-resistant bursting cells also remained unchanged by the effects of GABA and acetylcholine antagonists. It is concluded that cells with properties of regular and bursting endogenous pacemakers are found in the MS-DB.Institute of Biophysics, Academy of Sciences of the USSR, Pushchino-on-Oka. Translated from Neirofiziologiya, Vol. 19, No. 5, pp. 586–595, September–October, 1987.     

Soluble "high Km" 5'-nucleotidase activity in human T- and B-lymphoblasts: isolation and some properties

1. Activity of "high Km" 5'-nucleotidase was investigated in the soluble fractions from cultured human T- and B-lymphoblasts. 2. Using gel filtration chromatography and 5'-AMP-Sepharose 4B affinity chromatography, it separated high Km 5'-nucleotidases from other two different soluble nucleoside 5'-phosphomonoesterase activities. 3. The molecular mass of the high Km enzymes from T- and B-lymphoblasts were 210 and 200 kDa, respectively. The optimum pH was at 6.5, and the Km values for IMP and AMP were 0.4 and 0.9 mM, respectively. 4. These properties of high Km 5'-nucleotidases were similar to those previously described from different tissues. These data indicate that soluble high Km 5'-nucleotidase coexists with "low Km" enzyme.     

AMINE FORMATION FROM l-TRYPTOPHAN IN BRAIN SLICES

Abstract— Slices from four areas of guinea-pig brain (hypothalamus, corpus striatum, median ponsmedulla and cerebral cortex) were incubated with concentrations of l -[3-¹⁴C]tryptophan varying from 20 to 300 μ m . in the presence of 5 × 10^-5 m -pargyline. The formation of tryptamine and serotonin was studied.
Serotonin synthesis reached its highest level at a concentration of approx 80 μ m -tryptophan in all 4 brain areas. Activity was high in pons-medulla and hypothalamus but only about one third as high in corpus striatum and cortex.
Tryptamine formation continued to increase within the concentration range of tryptophan used. Activity was high in corpus striatum where, at 300 μ m -tryptophan, tryptamine formation exceeded serotonin formation, but was low in cortex and intermediate in pons-medulla and hypothalamus.
The possible formation of kynuramine and 5-hydroxykynuramine was also investigated. No evidence was obtained for the formation of 5-hydroxykynuramine. Traces of radioactivity were found corresponding to kynuramine, but these were insufficient to establish its formation with certainty. If formed. the rate of kynuramine synthesis did not exceed 2% of the combined formation of serotonin and tryptamine.     

Effects of metal contamination on the activity and diversity of carabid beetles in an ancient Pb-Zn mining area at Plombières (Belgium)

Carabid beetles were monthly sampled with pitfall traps in the ancient Pb-Zn mining area of Plombières during one year. Based on the total soil concentrations of lead, zinc, cadmium and copper, it was expected that zinc would probably have the most adverse effects on the populations. Activity and species richness of carabid beetles were, however, not significantly correlated with total zinc concentration nor with the water soluble and the calciumchloride extractable concentration. In fact, despite the high soil concentrations, carabid beetles did not seem to be affected in the study area. The apparent lack of effects at the high observed zinc concentrations is probably caused by the low bioavailability of zinc to the beetles in the litter of the study sites which was also reflected in the low observed water soluble zinc concentrations.     

Mechanisms of iron transport into rat erythroid cells

Three mechanisms of iron uptake by rat erythroid cells were identified, two with non-transferrin-bound iron (NTBI) and one with transferrin-bound iron (Fe-Tf). Uptake of NTBI occurred by a high affinity mechanism (K(m) approximately 0.1 microM). Activity of the high affinity mechanism was maximal in sucrose solution and of the low affinity mechanism in KCl solution. Both were inhibited by NaCl and by certain ion transport inhibitors, but they differed in their sensitivity to the various inhibitors. Fe-Tf uptake was also of high affinity (K(m) 0.1 microM). All the transport mechanisms show higher activity in reticulocytes than in mature erythrocytes, and all could provide iron for heme synthesis in reticulocytes. The results demonstrate certain conditions which should be followed in order to study high affinity transport of NTBI. These include use of a low packed cell volume in the incubation mixture, low iron concentrations (0.01-1.0 microM), short incubation times (up to 20 min), and low osmolality (approximately 200 mOsm/kg) during incubation with the NTBI and subsequent washing of the cells.     

Polymyxin B biosynthesis and tricarboxylic acid cycle enzymatic activity]

Activity of pyruvate dehydrogenase (PDG), isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase was found in the extracts of the cells of Bac. polymyxa 153, an organism producing polymyxin B. Dependence of the activity of the above enzymes on the carbon source in the medium, aeration conditions, strain features and culture age was shown. A low level of polymyxin B biosynthesis was observed at high activity of PDG and dehydrogenases of the tricarbonic acid cycle. Increased antibiotic production was recorded against the background of decreases values of the above enzyme activities.     

Activity Pattern of the Trawling Phyllostomid Bat,Macrophyllum macrophyllum,in Panamá1

We studied activity patterns of long‐legged bats, Macrophyllum macrophyllum (Phyllostomidae), in the Barro Colorado Nature Monument, Panamá, using radio‐telemetry. Activity of four males and five females equipped with radio‐transmitters were monitored for 4–7 entire nights each between April and July 2002. Bats exhibited maximum activity around dusk and high activity during the night. Males and females foraged for equal amounts of time in continuous flight (mean: 7 min, maximum 1 h) with interspersed resting phases (mean: 15 min, maximum 3 h). Activity of M. macrophyllum was sensitive to several factors. Time of emergence and return to day roost were correlated with time of sunset and sunrise, respectively. Maximum bat activity coincided with high abundance of aerial insects. Finally, heavy rain caused bats to reduce or cease flight activity. Direct observations and field video recordings support the assumption that M. macrophyllum employs two distinct foraging modes: trawling of insects from and capture of aerial insects at low heights above water. Combination of foraging modes gives M. macrophyllum high flexibility and efficiency in prey search. Activity, foraging mode, and morphology, which are similar to trawling bats from other families, distinguish M. macrophyllum from all other phyllostomid species and grant it access to open habitat above water, a habitat no other phyllostomid bat has conquered.     

The localization of enzymes in the cotyledons of Pisum arvense L. during germination

Summary Enzyme activity is not uniformly distributed through the cotyledon of Pisum arvense. Initially the peripheral region, certain scattered cells of the storage tissue and the procambium show a high level of activity of succinic dehydrogenase, cytochrome oxidase, acid phosphatase and esterase. Activity of acid phosphatase declines sharply after the first day of germination; activity of the other enzymes declines after about three days. In the storage tissue, where activity is lower initially, it declines after about five days and is correlated with the disappearance of the reserves. The pattern of alkaline phosphatase activity is similar except that activity is lower in the procambium but increases in the sieve-elements during differentiation of the phloem. 5-nucleotidase and glucose-6-phosphatase activity is low throughout the cotyledon but it also increases to a significant level in the sieve-elements. Activity of starch synthesizing enzymes is high in the parenchymatous bundle sheath, where they may be involved in the pathway from lipids to soluble carbohydrates.     

Reduced activity of juvenile hormone esterase in microsporidia-infected Lymantria dispar larvae

Infection of the fat body of Lymantria dispar (Lep.: Lymantriinae) larvae with the microsporidium Vairimorpha disparis has severe effects on juvenile hormone (JH) metabolism of the host. Beginning 8 days postinfection, activity of the JH degrading enzyme JH-esterase was significantly lower in the hemolymph of infected than uninfected larvae. Activity remained low as microsporidiosis progressed. JH titers were slightly elevated in infected larvae; the difference was not significant in most cases. This disturbance of JH metabolism may be due to generally impaired fat body functions and high demand for resources by the developing pathogen.     

Properties of the chaperonin complex from the halophilic archaeon Haloferax volcanii

The halophilic archaeon Haloferax volcanii has three genes encoding type II chaperonins, named cct1, cct2 and cct3. We show here that the three CCT proteins are all expressed but not to the same level. All three proteins are further induced on heat shock. The CCT proteins were purified by ammonium sulphate precipitation, sucrose gradient centrifugation and hydrophobic interaction chromatography. This procedure yields a high molecular mass complex (or complexes). The complex has ATPase activity, which is magnesium dependent, low salt-sensitive and stable to at least 75 degrees C. Activity requires high levels of potassium ions and was reduced in the presence of an increasing concentration of sodium ions.     

Changes in peroxidase activity and in peroxidase isozymes in carrot callus

Activity of soluble peroxidase and its isozyme patterns in carrot ( Daucus carota L.) callus after excision and transfer to fresh Murashige and Skoog (MS) culture medium was investigated. The activity decreased markedly until day 1 and then increased gradually during days 7–10 at room temperature. The rapid initial decrease of the activity was also observed at low temperature (2°C) as well as in the presence of cycloheximide. However, the subsequent increase in the peroxidase activity after day I was slower at low temperature than at room temperature, and was not detected in the presence of cycloheximide. Activity of catalase decreased slightly within 4 days and cycloheximide enhanced the decrease of the activity. Two cationic and one anionic peroxidase isozymes disappeared or decreased markedly within the first day and one cationic and anionic peroxidase recovered 3–6 days after excision.     

Nucleases activity in different segments of the human digestive tube compared to the incidence of carcinomas (histochemical study)

Summary The alkaline and acid DNase and RNase activity was histochemically investigated in biopsies from the human digestive tube. Activity of these enzymes in the mucosal epithelium in different segments of the digestive tube was compared to the statistical incidence of malignant tumors deriving from this tissue (carcinomas). It was found that the alkaline and acid nucleases activity was very intense in small intestine precisely in this segment where the incidence of carcinomas was low, whereas the low activity of these enzymes in the stomach and large intestine corresponded to the high incidence of carcinomas. This observation confirmed our previously elaborated hypothesis, according to which the low activity of nucleases in normal tissues appeared to be a predisposing factor for malignant transformation.It could be also supposed that the nucleases constitute some kind of double barrier mechanism protecting the genetical stability of the cell against foreign nucleic acid incorporation or production; alkaline nucleases being an extracellular and acid nucleases an intracellular barrier.     

Influence of mouse strain, infective dose and larval burden in the brain on activity in Toxocara-infected mice

Outbred LACA mice and inbred NIH mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4x250 ova) doses of Toxocara canis ova and the effect of infection on activity was examined with respect to: (i) the dose of ova administered and (ii) the number of larvae recovered from the brain. Larval recovery from the brain was significantly reduced in NIH mice compared to LACA mice for the 1000, 3000 and trickle doses. Mice from each strain were divided into larval intensity groupings based upon the number of larvae recovered from their brain. Activity for each mouse was measured pre- and post-infection by observing its behaviour in the home cage. Activity was assessed by monitoring six different independent categories of murine behaviour - ambulation, grooming, rearing, digging, climbing and immobility. Within each behavioural category, the duration of time spent at each behaviour per mouse within one thousandth of a second, the number of short bouts performed and the number of long bouts of behaviour performed were recorded over a 20 min period. Activity of LACA and NIH mice differed prior to infection. LACA mice spent more time immobile compared to NIH mice, which ambulated and climbed more. Variations in activity were also observed between groups of mice prior to infection. The effect of infection differed by strain, by dose and by larval intensity. Post-infection LACA mice became more immobile and ambulated less. NIH mice showed reduced immobility, but while ambulation decreased digging and climbing increased post-infection. Short bouts of activity remained unchanged among LACA mice post-infection but showed an increase for some behaviours in NIH mice.     

Regulation of spvR, the positive regulatory gene of Salmonella plasmid virulence genes

Abstract The regulation of the spvR promoter from the Salmonella dublin virulence plasmid was monitored using proter-reporter gene fusion constructs. Activity was dependent upon the presence of the spv region and was affected by the number of copies of the spv region present with the cell. Activity remained constant throughout exponential growth, and increased rapidly with the onset of stationary phase, under both aerobic and anaerobic conditions. Additionally, the level of spvR expression was controlled by the availability of iron, activity being greatest under low iron conditions in stationary phase. The spvA gene product negatively regulated spvR expression in a dose-dependent manner, indicating that SpvA provides a negative feedback mechanism for this operon.     

Glycogen synthase in the rat tapeworm, Hymenolepis diminuta--I. Enzyme activity during development and with crowding.

1. Activity of glycogen synthase (E.C. 2.4.1.11) in Hymenolepis diminuta (Cestoda: Cyclophyllidea) was investigated as a function of development and with crowding. 2. Synthase activity was low in the anterior and posterior ends of the worms and highest in the pregravid proglottids in the mid-portion of the strobila. 3. The enzyme activity increased during development of the cestode at least up to 15 days postinfection, but the increase in activity apparently was not due to conversion of the inactive to the active form. 4. Mature oncospheres also contained glycogen synthase, but the activity was lower than in strobilar tissues. 5. Synthase I activities and the proportion of total activity in the I form were generally higher in worms from high density (100 worm) infections than in those from low density (10 worm) infections.     

Characterization of ribonucleotide reductase activity from mouse L cells

We describe some fundamental properties of the cytidine 5'-diphosphate (CDP) and guanosine 5'-diphosphate (GDP) reductase activity from mouse L cells. Both activities increased in a nonlinear fashion at low protein concentrations; this may be due to dissociation of two protein subunits of the enzyme at very low concentrations. CDP reductase activity was greatly stimulated in the presence of ATP and required magnesium and iron for maximum activity. GDP reductase required 2'-deoxythymidine 5'-triphosphate for maximum activity. Also apparent Km values of 0.14 mmol/l for CDP and 0.05 mmol/l for GDP were determined from double reciprocal plots of velocity against substrate concentrations. Activity in extracts of logarithmically growing mouse L cells was very high indicating that attempts to purify the enzyme from this source should be rewarding.     

Temperature-sensitive gating in a descending visual interneuron, DCMD

Activity in neural circuits can be modified through experience-dependent mechanisms. The effects of high temperature on a locust visual interneuron (the descending contralateral movement detector, DCMD) have previously been shown to be mitigated by prior exposure to sub-lethal, elevated temperatures (heat shock, HS). Activity in the DCMD is reduced at high temperature in naïve animals (control), whereas HS animals show a maintained spike count at all temperatures. We examined whether this finding was due to direct effects of temperature on visual processing, or whether other indirect feedback mechanisms were responsible for the observed effect in the DCMD. Activity in the DCMD was elicited using a computer-generated looming image, and the response was recorded extracellularly. The temperature of visual processing circuits contributes directly to HS-induced plasticity in the DCMD, as maintaining the brain at 25°C during a thoracic temperature ramp eliminated the high frequency activity associated with HS. Removing ascending input by severing the thoracic nerve cord reduced DCMD thermosensitivity, indicating that indirect feedback mechanisms are also involved in controlling the DCMD response to increased thoracic temperature. Understanding how thermosensitive feedback within the locust affects DCMD function provides insight into critical regulatory mechanisms underlying visually-guided behaviors.