Swelling behaviour of alginate–chitosan microcapsules prepared by external gelation or internal gelation technology

Swelling behaviour is one of the important properties for microcapsules made by hydrogels, which always affects the diffusion and release of drugs when the microcapsules are applied in drug delivery systems. In this paper, alginate–chitosan microcapsules were prepared by different technologies called external or internal gelation process respectively. With the volume swelling degree (S_w) as an index, the effect of properties of chitosan on the swelling behaviour of both microcapsules was investigated. It was demonstrated that the microcapsules with low molecular weight and high concentration of chitosan gave rise to low S_w. Considering the need of maintaining drug activity and drug loading, neutral pH and short gelation time were favorable. It was also noticed that S_w of internal gelation microcapsules was lower than that of external gelation microcapsules, which was interpreted by the structure analysis of internal or external gelation Ca–alginate beads with the aid of confocal laser scanning microscope.     

The respiration and oxidative phosphorylation of the brain mitochondria in rats with different types of behavior]

Respiration and oxidative phosphorylation of brain mitochondria were studied in outbred rats with different types of behaviour in open-field test and in forced swimming test. It was found that in rats with "active" type of behaviour (with high locomotor activity and low level of depressiveness) the brain mitochondria have at succinate oxidation a higher rate of respiration in active metabolic state and in presence of uncoupler 2,4-DNP, and a higher rate of ADP phosphorylation than in rats with "passive" type of behaviour (with low locomotor activity and high and moderate levels of depressiveness). Thus rats with active type of behaviour have a higher succinate oxidase activity than rats with passive type of behaviour. It is supposed that revealed differences in brain energy metabolism may affect the dominance of certain type of behaviour.     

The intercentral relations of the frontal cortex and limbic structures of the brain in dogs]

In 3 dogs with implanted electrodes, in conditioned experiments correlation of the bioelectrical processes was studied by coherence function calculation of the hippocampus, hypothalamus, amygdala and frontal cortex biopotentials. It was shown, that the level of maximum values of coherence function of bioelectrical oscillations, led from various pairs of the studied brain structures significantly differed both in magnitude and frequency at which the greatest synchronization of biopotentials was noticed. In one dog with a high degree of connection between the hippocampus and hypothalamus biopotentials oscillations, a low synchronization of the frontal cortex and amygdala oscillations was found; in two other animals with a higher level of coherence between the oscillations of the frontal cortex and amygdala biopotentials, a lower degree of connection between the oscillations led from the hippocampus and hypothalamus was revealed. Synchronization of the biopotentials of the hippocampus and frontal cortex and also of the hippocampus and amygdala biopotentials proved to be low in all experimental dogs, what additionally testifies to different role of these structures in organization of the behaviour.     

Individual differences in searching behaviour and spatial foraging consistency in a central place marine predator

Consistent intra‐population variability in foraging behaviour is found among a wide range of taxa. Such foraging specialisations are common among marine vertebrates, yet it is not clear how individuals repeatedly locate prey or foraging sites at ocean‐wide scales. Using GPS and time‐depth loggers we studied the fine‐scale foraging behaviour of central‐place northern gannets Morus bassanus at two large colonies. First, we estimated the degree of consistency in individual foraging routes and sites across repeated trips. Second, we tested for individual differences in searching behaviour in response to environmental covariates using reaction norms, estimated from mixed effect models. Adult gannets tracked over multiple foraging trips showed repeatable between‐individual differences in terminal points and departure angles of foraging trips, but low repeatability in trip duration and trip length. Importantly, individual birds showed highly repeatable dive locations, with consistently different environmental conditions (such as copepod abundance), suggesting a high degree of foraging site specialisation. Gannets also showed between‐individual differences in searching behaviour along environmental gradients, such that individuals intensified searching under different conditions. Together these results suggest that widespread individual foraging consistency may represent specialisation and be linked with individual responses to environmental conditions. Such divergent searching behaviour could provide a mechanism by which consistent foraging behaviour arises and is maintained among animals that forage across large spatial scales.     

FURTHER NOTES ON PAIRING AND SUBMISSIVE BEHAVIOUR OF THE RED-LEGGED PARTRIDGE ALECTORIS RUFA

1. The submissive display is described. It is sometimes given when the bird appears to be simultaneously frightened and attracted by a fellow member of the species.
2. The pairing behaviour of some individual captive birds is described. Some degree of mutual fear and hostility seems to be a necessary correlate of sexual attraction in this species. Birds that know and are at ease with one another do not pair.
3. A young male showed (in autumn) behaviour similar to that of a female ready to pair when introduced to an old and aggressive male. A possible biological function of such behaviour is suggested.     

Biochemical investigation of two responses involved in the feeding behaviour of Acanthaster planci (L.). II. Isolation and characterization of chemical stimuli

Feeding behaviour is induced in the crown-of-thorns starfish, Acanthaster planet (L.), by two kinds of chemical stimulus originating in coral. One is macromolecular, and the other of low molecular weight, largely accounted for by small peptides and amino acids.It is found that, under experimental conditions, starfish rapidly habituate to a chemical stimulus which at first strongly induces feeding behaviour.The pronounced withdrawal response which occurs when a crude extract of coral is applied to the starfish (a response apparently identical with that evoked by contact with live coral) is caused by a component which corresponds closely in chromatographie behaviour with proline. Proline itself produces the response, but is present at too low a concentration in coral to account for the observed activity.     

Electron microscopic localization of a fucose-binding protein in acrosome reacted boar spermatozoa by the fucosyl-peroxydase-gold method

Summary In this study we have examined the behaviour and the localization of the fucose-binding protein (FBP) in boar spermatozoa during ionophore induced acrosome reaction (AR) by means of normal TEM and specimen preparation in toto. During early stages of AR the FBP is first localized at the border between equatorial segment and anterior acrosome. With the propagation of the AR the FBP is dramatically expressed and visible over the entire surface of the acrosome and equatorial segment. TEM pictures of this stages show that the FBP is associated with the OAM. At later stages of AR, when acrosomal ghost formation occur, the FBP is associated with the acrosomal ghost, and equatorial segment and to a very low degree also with the IAM. It is concluded from this data that the FBP is responsible for the specific binding of the ghost-sperm unit to the zone pellucida.     

Electron microscopic localization of a fucose-binding protein in acrosome reacted boar spermatozoa by the fucosyl-peroxidase-gold method

In this study we have examined the behaviour and the localization of the fucose-binding protein (FBP) in boar spermatozoa during ionophore induced acrosome reaction (AR) by means of normal TEM and specimen preparation in toto. During early stages of AR the FBP is first localized at the border between equatorial segment and anterior acrosome. With the propagation of the AR the FBP is dramatically expressed and visible over the entire surface of the acrosome and equatorial segment. TEM pictures of this stages show that the FBP is associated with the OAM. At later stages of AR, when acrosomal ghost formation occur, the FBP is associated with the acrosomal ghost, and equatorial segment and to a very low degree also with the IAM. It is concluded from this data that the FBP is responsible for the specific binding of the ghost-sperm unit to the zona pellucida.     

Effect of previous experience in reacting to a danger signal on "open field" behavior in the rat

Modification of rats behaviour in an "hopen field" test was investigated, induced by an acoustic stimulus, previously subjected to conditioning in a shuttle chamber in experiments with possibility and impossibility of avoidance from electrical shock. It has been established that presentation of a stimulus having the meaning of a danger signal, in a new situation, significantly suppresses investigating behaviour of rats, whereas the stimulus which had not been subjected to conditioning exerts no marked effect on behaviour. The greatest suppression was observed in rats with "learned helplessness". This fact suggests that the degree of suppression of the behaviour in an open field in response to a danger signal, depends on the animal's previous experience in reacting to this signal.     

Emotion Regulation Moderates the Association between Empathy and Prosocial Behavior

Theory and evidence suggest that empathy is an important motivating factor for prosocial behaviour and that emotion regulation, i.e. the capacity to exert control over an emotional response, may moderate the degree to which empathy is associated with prosocial behaviour. However, studies to date have not simultaneously explored the associations between different empathic processes and prosocial behaviour, nor whether different types of emotion regulation strategies (e.g. cognitive reappraisal and expressive suppression) moderate associations between empathy and prosocial behaviour. One hundred–and-ten healthy adults completed questionnaire measures of empathy, emotion regulation and prosocial tendencies. In this sample, both affective and cognitive empathy predicted self-reported prosocial tendencies. In addition, cognitive reappraisal moderated the association between affective empathy and prosocial tendencies. Specifically, there was a significant positive association between empathy and prosocial tendencies for individuals with a low or average tendency to reappraise but not for those with a high tendency to reappraise. Our findings suggest that, in general, empathy is positively associated with prosocial behaviour. However, this association is not significant for individuals with a high tendency for cognitive reappraisal.     

Adsorption of an ionic homopolypeptide to a flat surface induced by pH change

This paper presents a model for pH-dependent adsorption of an ionic homopolypeptide with secondary structure on a flat surface. This model is developed by generalization of a discrete model of semistiff chain with short-range interaction, between homopolypeptide chain and surface. The presence of intramolecular repulsive interaction as well as secondary structure is introduced here by modified Zimm-Bragg stabilization parameters. The model predicts that in the case of low degree of ionization, the adsorption behaviour of an ionic and non-ionic homopolypeptide are qualitatively similar (i.e. both show a second-order phase-transition, characteristic of this phenomenon). We also illustrate the prediction of the model about the critical absorption energy in the case of selective interaction, and show that a discontinuity in the melting-temperature behaviour appears when the pH is tuned to a critical pH value (pHc).     

A comparison of the correcting behaviour exhibited by two milkweed bugs, Oncopeltus fasciatus and Lygaeus kalmii

ABSTRACT. Adults and nymphs of two species of milkweed bugs, Oncopeltus fasciatus and Lygaeus kalmii , were studied with respect to their optomotor responses, as exhibited by the laboratory phenomenon of correcting behaviour on mazes. It was found that the O.fasciatus nymphs failed to correct while the other three groups all exhibited correcting behaviour. The differences in correcting behaviour were attributed to differences in such ecological variables as degree of socialness, nature of food source, and foraging strategies.     

Suppression of GABA-induced abstinence behaviour in naive rats by morphine and bicuculline.

Intraperitoneal administration of n-dipropylacetate (DPA) to naive rats produced abstinence behaviour including shaking, digging, hunchback posture, piloerection and ptosis during 15 min and increased motor activity considerably. Treatment with a subconvulsive dose of the GABA antagonist bicuculline suppressed this DPA-induced abstinence behaviour, indicating that GABA was increased at receptor sites. Also morphine in a low dose of 1 mg/kg suppressed this behaviour, while administration of naloxone after morphine treatment could release the abstinence behaviour. Simultaneous treatment with morphine and naloxone or naloxone alone were without effect. The administration to DPA treated rats of doses higher than 1 mg/kg morphine resulted in a severe depression of motor activity. It is concluded that an increased availability of GABA at its receptor sites plays an important role in the behaviour observed after DPA administration. The experiments with morphine and naloxone suggest that morphine receptors are involved in DPA-induced abstinence behaviour.     

Social-economic inequality in mortality among older mem amd women. Research on the role of health, life style, parental socio-economic status and psychosocial conditions

This article describes to what degree socio-economic differences exist among community living older men and women, and to what degree these differences are to be explained by health, behaviour, childhood and psychosocial conditions. The data are available from 1427 men and 1503 women (aged 55-85), participating in the Longitudinal Aging Study Amsterdam (LASA) in 1992/1993. As indicators of socio-economic status (ses) we used the highest level of education and net monthly income. Age-adjusted mortality risks for men and women with low income and for men with a low level of education are about 1.5 times as high as for to the persons with high income and educational level. Among men, but not among women, the difference in mortality risk between low and high status persons remains after adjustment for age, health status, and several risk factors. Differences in lifestyle, parental ses and psychosocial characteristics explain little to nothing of the age-adjusted ses-differentiation in mortality. It is concluded that ses-inequalities in mortality are present among Dutch men and, to a lesser extent among women, until high age, and are partly explained by the relatively large health problems of the lower status group.     

Comparative aggression in Sceloporus virgatus, S. undulatus consobrinus, and S. u. tristichus (Sauria: iguanidae).

Aggressive behaviour in both sexes of Sceloporus virgatus, S. undulatus consobrinus, and S. u. tristichus were compared by introducing a conspecific to a resident lizard in the field. Males of S. u. consobrinus exhibited high intensity aggression more commonly than did males of the other forms. Of the females, S. u. tristichus showed the greatest propensity for aggressive behaviour; S. u. consobrinus showed the least. In males, degree of aggression was correlated positively with degree of sexual dichromatism. The high degree of aggression in male S. u. consobrinus may be selectively advantageous because of (1) low density increasing space between females, (2) low density reducing selection against a relatively high frequency of violent fighting, and (3) high predation favouring lizards that do not leave their sites upon intrusion of another male. High aggression in female S. u. tristichus may be selectively advantageous because of (1) higher density leading to reduced food supply and fewer egg-laying sites, and (2) lower predation reducing selection against mobility and fighting in females.     

Multiple mode of action of the feeding deterrent,toosendanin, on the sense of taste in Pieris brassicae larvae

Toosendanin, a tetranortriterpenoid isolated from the bark of Melia toosendan, is a feeding deterrent for larvae of Pieris brassicae. By using electrophysiological techniques, it was found that toosendanin stimulates a deterrent receptor cell located in the medial maxillary sensillum styloconicum. Toosendanin also inhibits responses of both the sugar and glucosinolate receptor cell, which are localized in the lateral sensillum styloconicum. The degree of inhibition of the sugar receptor increases with increasing sucrose concentration. The glucosinolate receptor cell shows a reversed reaction: inhibition by toosendanin decreases with increasing sinigrin concentration. Inhibitory effects occur at a toosendanin concentration as low as 10^–9 M and are dose dependent. The taste neurons that respond to amino acids or deterrents in the lateral sensillum, however, are not affected by toosendanin. It is concluded that the sensory code underlying feeding behaviour is modulated by toosendanin via several different peripheral sensory mechanisms.     

The genetic and environmental basis of adaptive differences in shoaling behaviour among populations of Trinidadian guppies,Poecilia reticulata

The degree of plasticity an individual expresses when moving into a new environment is likely to influence the probability of colonization and potential for subsequent evolution. Yet few empirical examples exist where the ancestral and derived conditions suggest a role for plasticity in adaptive genetic divergence of populations. Here we explore the genetic and plastic components of shoaling behaviour in two pairs of populations of Poecilia reticulata (Trinidadian guppies). We contrast shoaling behaviour of guppies derived from high‐ and low‐predation populations from two separate drainages by measuring the shoaling response of second generation laboratory‐reared individuals in the presence and absence of predator induced alarm pheromones. We find persistent differences in mean shoaling cohesion that suggest a genetic basis; when measured under the same conditions high‐predation guppies form more cohesive shoals than low‐predation guppies. Both high and low‐predation guppies also exhibit plasticity in the response to alarm pheromones, by forming tighter, more cohesive shoals. These patterns suggest a conserved capacity for adaptive behavioural plasticity when moving between variable predation communities that are consistent with models of genetic accommodation.     

Effect of emotionality, exploratory activity and pain sensitivity on manifestation of agonistic behavior in the mouse

Mice of C57BL/6J line with higher exploratory and motor activities and with lower emotionality and pain threshold recorded in standard tests, as compared with the animals of CBA/Lac line, have also been found to manifest a more expressed aggression in their intermale contacts in reaction to a syngeneous partner. It is suggested that the studied physiological and behavioural parameters may determine in considerable degree the character of aggressive and submissive mice behaviour in an agonistic interaction.     

Heritability of dispersal in the great reed warbler

Dispersal is commonly considered to be a condition‐dependent behaviour with no or low heritability. Here, we show that dispersal in the great reed warbler (Acrocephalus arundinaceus) has a high heritability. Analyses of capture–recapture data of male great reed warblers gathered from the species’ whole Swedish breeding range revealed a remarkable offspring–parent resemblance in dispersal behaviour (philopatry vs. inter‐population dispersal). Also, the degree of dispersal differed between cohorts, which shows that dispersal was partly conditionally dependent. The offspring to mid‐parent estimate of heritability was 0.50. In a previous study of the same data set of male offspring, we did not detect associations between dispersal and several relevant environmental, parental and offspring condition factors. Thus, our results indicate that variation in dispersal partly has a genetic basis in great reed warblers.     

Play-like behaviour: An essay in speculative ethology

It is claimed that certain processes of individual behaviour and of interaction between individuals run parallel. Such parallels are seen along three axes: antagonism-coordination, constriction-expansion and neutral-play-like. Characteristics of ritualized behaviour and play are analysed and the two categories of behaviour are compared in detail. They are shown to differ largely in degree of expansion. They also differ along the antagonism-coordination axis. Both are play-like. A theory comprising both ritualized behaviour and play is attempted. The concept of field interaction is introduced. The physical theory of elect ro-magnetism is used as a conceptual model. Positive and problematic aspects of the theory are discussed: Is the behavioural field polarised or not? The relationship between aggression and play-like behaviour is considered, both as a motivational problem and in phylogenetic perspective. Some limits to the theory are indicated. Relationships of the theory to some other theories are briefly discussed.