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PubMed1990

Time of repletion of subadult Ixodes ricinus ticks feeding on diverse hosts.

For a comparison of the times of day at which the subadult stages of Ixodes ricinus detach from nocturnal vs diurnal hosts, these ticks were placed on a variety of indigenous and experimental animals. The time of detachment appears to depend more on properties of the host than on the periodicity of tick behavior. Ticks on rodents, regardless of host periodicity, tended to detach late in the afternoon; those on the hedgehog detached around midnight, and those on lizards and birds, during the morning. Ticks on carnivores (dog, cat) detached throughout the daylight hours. The ability of these parasites to survive to the next developmental stage and, ultimately, to come into contact with another suitable host may be influenced by the identity of the host and, hence, by the circumstances of detachment. Subadult I. ricinus probably concentrate in the host's nest when feeding on mammals but are scattered over the ground when feeding on lizard or avian hosts, an aspect of engorgement behavior that may profoundly affect the capacity of this tick as a vector of agents of Lyme disease and other infections.

Animals↗
PubMed1987

Induction of maternal behavior in incubating and non-incubating hens: influence of hormones.

Maternal responses and variations in plasma levels of prolactin and testosterone have been studied in incubating and in non-incubating, non-laying hens during forced adoption experiments. The results demonstrate the ability of incubating hens to display complete maternal behavior as early as the 10th day of incubation after being exposed to stimulation by chicks during one night. Maternal responses also emerged in non-laying hens but more gradually. In both groups, a decline in plasma testosterone occurred after the introduction of the chicks and, in the incubating hens, prolactin levels fell as they abandoned their nests.

Animals↗
PubMed1996

Adhesive and migratory behaviors of nevus cells differ from those of epidermal melanocytes and are not linked to the histological type of nevus.

It has been postulated that acquired nevi undergo life span continuous evolution from junctional, presumably in radial expanding phase at the dermal epidermal junction, to compound and then to dermal nested nevi. In an attempt to correlate the morphology of nevi with biological data, we have investigated whether migratory and adhesive phenotypes of nevus cells could account for histological patterns and possible spatiotemporal changes in nevi. Nevus cells were cultured from compound and dermal nevi and compared to normal epidermal cultured melanocytes from children and adults. AR nevus cells showed similar in vitro adhesive and migratory indexes on laminin-1, laminin-5/nicein, fibronectin, or collagen IV substrates, suggesting that these intrinsic characteristics do not account for the tendency to dermal nesting and/or to radial growth along the dermal-epidermal junction. The cells from epidermal and dermal parts of compound nevi migrated similarly across a reconstituted basement membrane. The results show that intrinsic adhesive and migratory behaviors of nevus cells were not associated with a histological type of nevus. Interestingly, differences in migratory phenotype and intercellular adhesion capacities between nevus cells and normal melanocytes indicated that they could represent different melanocytic cell subpopulations. Finally, melanocytes from adults and children expressed similar levels of the same integrins as all nevus cells but showed differences in function of both alpha3 and alpha6 integrin subunits and in migratory/adhesive behaviors, which may suggest different states of melanocyte maturation.

Adult↗
PubMed1996

Infants' responses to facial and vocal emotional signals in a social referencing paradigm.

The independent effects of facial and vocal emotional signals and of positive and negative signals on infant behavior were investigated in a novel toy social referencing paradigm. 90 12-month-old infants and their mothers were assigned to an expression condition (neutral, happy, or fear) nested within a modality condition (face-only or voice-only). Each infant participated in 3 trials: a baseline trial, an expression trial, and a final positive trial. We found that fearful vocal emotional signals, when presented without facial signals, were sufficient to elicit appropriate behavior regulation. Infants in the fear-voice condition looked at their mothers longer, showed less toy proximity, and tended to show more negative affect than infants in the neutral-voice condition. Happy vocal signals did not elicit differential responding. The infants' sex was a factor in the few effects that were found for infants' responses to facial emotional signals.

Affect↗
PubMedDate not supplied

Fimbria-fornix lesions disrupt the dead reckoning (homing) component of exploratory behavior in mice.

Exploration is the primary way in which rodents gather information about their spatial surroundings. Thus, spatial theories propose that damage to the hippocampus, a structure thought to play a fundamental role in spatial behavior, should disrupt exploration. Exploration in rats is organized. The animals create home bases that are central to exploratory excursions and returns, and hippocampal formation damage alters the organization of exploration by disrupting returns. Mice do not appear to readily establish home bases in novel environments, thus, for this species, it is more difficult to establish the contribution of the hippocampus to exploration. The purpose of the present study was threefold: develop a task in which mice center their exploration from a home base, determine whether the exploratory behavior is organized, and evaluate the role of fimbria-fornix lesions on exploration. Mice were given a novel exploratory task in which their nesting material was placed on a large circular table. Video records of control and fimbria-fornix mice were made in both light and dark (infrared light) conditions. Exploration patterns (outward trips, stops, and homeward trips) were reconstructed from the video records. Control mice centered their activity on their bedding, from which they made circuitous outward trips marked by many stops, and periodic direct returns. The bedding-centered behavior and outward trips of the fimbria-fornix mice were similar to those of the control mice, but significantly fewer direct return trips occurred. The direct homeward trips observed under light and dark conditions were consistent with a dead-reckoning strategy, in which an animal computes its present position and homeward trajectory from self-movement cues generated on the outward trip. Because the fimbria-fornix lesions disrupted the homeward component of exploratory trips, we conclude that the fimbria-fornix may contribute to dead reckoning in mice. The results also show that the home-bedding methodology facilitates the establishment of a home base by mice, thus providing a useful methodology for studies with mice.

Animals↗
PubMed1996

Dichotomy of astrocytoma migration and proliferation.

Astrocytomas often show high rates of local invasion that lead to local recurrence of the disease. Histologically, the most highly invasive astrocytoma cells are detected in isolation rather than as nests of tumor. Our study attempted to determine whether the migratory response to extracellular substrates influences the proliferative behavior of these highly invasive cells. The preferential and specific migratory response of human astrocytoma cells to extracellular matrix proteins was assessed by a microliter scale migration assay. Growth curve studies on protein ligands permissive (merosin) for cell migration indicated that the lag phase was protracted compared with cells seeded on non-permissive proteins (vitronectin). Once a certain cell density was reached, logarithmic proliferation was indistinguishable on the different proteins. The proliferation index of populations of cells migrating on merosin and vitronectin was measured by both BrdU incorporation and MIB-1 immunocytochemistry labeling. Cells seeded on vitronectin showed higher proliferation throughout the population than cells seeded on merosin. On merosin, the more migratory cells at the periphery were less proliferative than non-migratory cells in the central region of that population. The integrin-associated signal transduction protein, p125FAK, was heavily localized in the membrane of non-migrating cells and largely absent in migrating astrocytoma cells. We conclude that temporally, proliferation and migration are mutually exclusive behaviors. Cell density or non-permissive substrates that inhibit cell motility favor a more proliferative phenotype. Conversely, active migration suppresses cell proliferation.

Astrocytoma↗
PubMed1995

Developmental neurotoxicity of carbon monoxide.

The results of recent studies dealing with behavioral and electrophysiological dysfunctions induced in rat offspring by prenatal exposure to relatively mild CO concentrations (75 and 150 ppm) have been reviewed in the present paper. In particular, gestational exposure to CO produced the following behavioral changes: (i) reduction in the minimum frequency of ultrasonic calls emitted by rat pups removed from their nest; (ii) decrease in ultrasonic responsiveness to a challenge dose of diazepam; (iii) alterations in the acquisition of an active avoidance task. The electrophysiological changes induced by prenatal CO in peripheral nervous system are as follows: (i) increase in time constants of sodium current inactivation; (ii) increase in the percentage of the maximum number of activatable sodium channels at the normal resting potential; (iii) negative shift of sodium current reversal potential. Moreover, results of ongoing researches on peripheral myelinogenesis in rats exposed to CO during gestation will be also summarized.

Animals↗
PubMed1999

Pathogen alarm behavior in a termite: A new form of communication in social insects

Dampwood termites, Zootermopsis angusticollis, show an alarm response after detecting the presence of spores of the pathogenic fungus Metarhizium anisopliae. Termites in direct contact with a high concentration of spores (10(7) spores/ml) show a striking vibratory display which appears to convey information about the presence of pathogens to nearby unexposed nestmates through substrate vibration. Nestmates not directly in contact with spores that perceive the vibrational signal increase significantly their distance from the spore-exposed vibrating termites, apparently to escape from the source of infection. The fleeing response is not induced by the presence of the spores alone or by pheromones, and requires the perception of the vibrations propagated through the substrate. This "pathogen alarm behavior" appears to be a previously unrecognized communication mechanism that allows termites to reduce disease risks within the nest.

Journal Article↗
PubMed2005

Dufour's gland secretion as a repellent used during usurpation by the slave-maker ant Rossomyrmex minuchae.

In slave-making ants, the invasion of the host colony by newly mated queens is a critical stage. We studied the strategy used by Rossomyrmex minuchae queens to invade their host Proformica longiseta. Field observations revealed that queens enter the host nest unchallenged by the host workers in the vicinity of the nest entrance. Pre-usurpation queens were found to possess a highly inflated Dufour's gland, which considerably reduces in size after successful usurpation. Chemical analysis of these queen glands revealed tetradecanal to be the major product in pre-usurpation Rossomyrmex queens, but to be almost absent in queens that have been adopted by P. longiseta. We consequently hypothesized that tetradecanal is a repellent that is used by queens to prevent host worker aggression. We tested its repellent effect by attempting to deter starved, highly motivated workers from a droplet of honey. Tetradecanal indeed proved to be highly repellent both to host worker P. longiseta and non-host worker Formica selysi. It was even more powerful than limonene, a reported general ant repellent. These results are consistent with the hypothesis that R. minuchae queens use Dufour's gland secretion as a weapon during nest usurpation. The general use of tetradecanal as a defensive compound, and its seemingly non-specific repellent effect on ants, indicate that it may act as a general ant repellent. Its adoption by R. minuchae queens thus provides them with an efficient defensive and offensive chemical weapon during their long and risky search for new host nests.

Agonistic Behavior↗
PubMed2002

Egg quality in furnished cages for laying hens--effects of crack reduction measures and hybrid.

Egg quality, egg production, and hen use of facilities, with respect mainly to proportion of eggs laid in nests and bird locations after lights-out, were studied in furnished-cage models for six or eight birds. In these cages, most of the eggs are laid in the 25 cm wide nest, i.e., egg laying is concentrated to a much smaller area compared with conventional cages. The study (20 to 80 wk of age) used 1,296 hens of three genotypes Hy-Line White, Hy-Line Brown, and Lohmann Selected Leghorn. Conventional four-hen cages were included as a reference. We separately studied the effects on the proportion of eggs cracked by egg saver wires in front of the egg cradle, long nest curtains, and position of nest opening (rear or front) with 30 or 100% of the nest bottom being lined with AstroTurf. Egg saver wires and long nest curtains lowered the proportions of cracked eggs significantly by softly catching and reducing the speed of the eggs before entering the egg cradle. The position of the nest opening affected none of the measured parameters. Less lining in the bottom of the nest, i.e., a reduction to 30% coverage, resulted in significantly higher proportions of dirty eggs and lower proportions of eggs laid in nests. Hybrid differences were found in most of the measured traits. We concluded that devices like egg savers and long nest curtains are effective measures in reducing cracks in furnished cages, where egg laying is concentrated to a much smaller area than in conventional cages. Reduction of the bottom lining to 30% makes nests less attractive to birds laying eggs.

Animals↗
PubMed2000

Sn/Ge(111) surface charge-density-wave phase transition

Angle-resolved photoemission has been utilized to study the surface electronic structure of 1 / 3 monolayer of Sn on Ge(111) in both the room-temperature (sqrt[3]xsqrt[3] )R30 degrees phase and the low-temperature ( 3x3) charge-density-wave phase. The results reveal a gap opening around the ( 3x3) Brillouin zone boundary, suggesting a Peierls-like transition despite the well-documented lack of Fermi nesting. A highly sensitive electronic response to doping by intrinsic surface defects is the cause for this unusual behavior, and a detailed calculation illustrates the origin of the ( 3x3) symmetry.

Journal Article↗
PubMed2002

Reduction of brain volume correlates with behavioral changes in queen ants.

The behavior of reproductive female ants distinctly changes during the transition from virgin to mature, egg-laying queen. A winged female ant flies only once during her lifetime when she engages in the nuptial flight. Once she is mated she sheds her wings, excavates a nest and starts laying eggs, the basis for her future colony. We show for two species of harvester ants that this transition is accompanied by changes in the performance of behavioral tests: flying virgins are positively phototactic and prefer open areas, whereas young queens prefer the dark, avoid open areas and, given the opportunity, dig into the soil. These behavioral changes coincide with morphological changes in the brain. The brains of mature queens are significantly smaller than those of virgin females at the time of their mating flight. A disproportionately large shrinkage occurs in the medulla and other parts of the visual system during the early adult life of the queen. The brain reduction appears to be adaptive as mature queens show reduced behavioral repertoires and live in the dark. In contrast to virgin females, they do not rely on vision and might increase their fitness by reducing metabolically costly neural tissue.

Animals↗
PubMed1996

Intra-abdominal desmoplastic small cell tumors: report of two cases.

Two young adults that presented with intra-abdominal desmoplastic small cell tumors (DSCT) without any evidence of a primary site are described. Both cases share the clinical characteristic features of this rare tumor which include predominant intra-abdominal location as initial presentation, nesting pattern of growth, intense desmoplastic reaction, immunohistochemical reactivity for epithelial, neural and muscle markers, and highly aggressive behavior. Aggressive chemotherapy with a cisplatin-containing regimen was the main therapy to our patients. Up to the present, both cases are alive with disease. The survival is 18 and 15 months from the initial diagnosis, respectively. Interestingly, one of the cases encountered an episode of cerebral infarction at the territory of the left middle cerebral artery 12 days after the first cycle of chemotherapy. This is a previously unrecognized manifestation for this tumor type. This causal relationship between chemotherapy and an acute vascular event is the most likely explanation for our patient's stroke.

Abdominal Neoplasms↗
PubMed2006

Phylogenetic analysis of honey bee behavioral evolution.

DNA sequences from three mitochondrial (rrnL, cox2, nad2) and one nuclear gene (itpr) from all 9 known honey bee species (Apis), a 10th possible species, Apis dorsata binghami, and three outgroup species (Bombus terrestris, Melipona bicolor and Trigona fimbriata) were used to infer Apis phylogenetic relationships using Bayesian analysis. The dwarf honey bees were confirmed as basal, and the giant and cavity-nesting species to be monophyletic. All nodes were strongly supported except that grouping Apis cerana with A. nigrocincta. Two thousand post-burnin trees from the phylogenetic analysis were used in a Bayesian comparative analysis to explore the evolution of dance type, nest structure, comb structure and dance sound within Apis. The ancestral honey bee species was inferred with high support to have nested in the open, and to have more likely than not had a silent vertical waggle dance and a single comb. The common ancestor of the giant and cavity-dwelling bees is strongly inferred to have had a buzzing vertical directional dance. All pairwise combinations of characters showed strong association, but the multiple comparisons problem reduces the ability to infer associations between states between characters. Nevertheless, a buzzing dance is significantly associated with cavity-nesting, several vertical combs, and dancing vertically, a horizontal dance is significantly associated with a nest with a single comb wrapped around the support, and open nesting with a single pendant comb and a silent waggle dance.

Animals↗
PubMed1989

Effects of preoptic and hypothalamic lesions in female turkeys during a photoinduced reproductive cycle.

Prolactin (Prl) is released by electrical stimulation in the turkey hypothalamus and preoptic area (POA). Possible trajectories for POA efferents to the median eminence (ME) were tested by placing lesions in the POA, the lateral hypothalamus (LHy), or the ventromedial nucleus of the hypothalamus (VMN) of reproductively quiescent turkey hens, then subjecting them to long photoperiods while monitoring their blood Prl levels and nesting activities. In addition, lesions were made in the VMN of a group of incubating hens to learn whether the lesions would cause the elevated Prl levels to fall or interfere with incubation behavior. Lesions in medial POA, LHy, or VMN prevented the onset of incubation and prevented the large rise in Prl associated with it. However, these lesions did not interfere with the initial, more gradual Prl rise caused by increasing daylengths. Lesions in LHy or VMN appeared to interfere with a pathway lying laterally from POA to ME. Electrical stimulation in medial POA, which caused an increase in circulating Prl, failed to do so in hens with LHy or VMN lesions. Lesions in the VMN of incubating hens caused them to leave the nest and suffer a large decline in Prl, both within 48 h. It is tentatively suggested that incubation behavior and its associated elevated Prl are prevented by the POA lesions and that lesions in LHy or VMN, which mimic POA lesion effects, interfere with POA efferents projecting to ME.

Animals↗