The expression of messenger RNAs coding for growth factors, their receptors, and eph-class receptor tyrosine kinases in normal and ototoxically damaged chick cochleae

Messenger RNAs coding for growth factors and receptor tyrosine kinases were measured by quantitative competitive and by semi-quantitative reverse-transcription polymerase chain reaction in whole and dissected chick inner ears. The fibroblast growth factor (FGF) receptor 1 chick embryonic kinase (CEK) 1 was expressed in all structures examined (otocyst, hatchling whole cochlea, cochlear nerve ganglion, and cochlear and vestibular sensory epithelia), although slightly more heavily in the otocyst. The related fibroblast growth factor receptors CEK 2 and 3 were preferentially expressed in the nerve ganglion and in the vestibular sensory epithelium, respectively. FGF 1 mRNA was low in early development, increasing to mature levels at around embryonic age 11 days, while FGF2, mRNA was expressed at constant levels at all ages. In response to ototoxic damage, FGF1 mRNA levels were increased in the early damaged cochlear sensory epithelium. Immunohistochemistry for CEK1 showed that normal hair cells expressed the receptor heavily on the hair cell stereocilia, while with early damage, CEK1 came to be expressed heavily on the apical surfaces of the supporting cells. In normal chicks, the CEK4 and CEK8 eph-class receptor tyrosine kinases were expressed relatively heavily by the cochlear nerve ganglion, and CEK10 was expressed relatively heavily by the cochlear hair cell sensory epithelium. The results suggest that the FGF system may be involved in the response of the cochlear epithelium to ototoxic damage. The eph-class receptor tyrosine kinase CEK10 may be involved in cell interactions in the cochlear sensory epithelium, while CEK4 and CEK8 may play a role in the cochlear innervation.

Type 1 and Type 2 cytokines: from basic science to fungal infections

At the present time, it is clear that Th1 responses afford protection against the fungi; however, the development, maintenance and function of the protective immune responses are complex mechanisms and are influenced by multiple factors. The route of infection has been shown to affect initial cytokine production and, consequently, the induction of protective Th1 responses. The ability of different isolates of the same fungal agent to induce and sustain a protective response has also been emphasized. Protective immune responses have been shown to vary in genetically different mouse strains after infection. In addition, these protective responses, such as cellular influx and cytokine production, also vary within the same animal depending on the tissue infected. The functional dominance of certain cytokines over others in influencing development and maintenance of protective responses has been discussed. Certain cytokines may act differently in hosts lacking important components of their innate or immune repertoire. It is evident from these presentations that a more comprehensive understanding of the protective mechanisms against different fungal agents is emerging. However, there is still much to learn before cytokine modulatory therapy can be used effectively without risk in the human host.

T-DNA tagging and characterisation of a novel meristem-specific promoter from tobacco

We have evaluated T-DNA mediated plant promoter tagging, with a left-border-linked promoterless firefly luciferase (luc) construct, as a strategy for the isolation of novel plant promoters. In a population of approximately 300 transformed tobacco plants, IO lines showed LUC activity, including novel tissue-specific and developmental patterns of expression. One line, showing LUC activity only in the shoot and root apical meristems, was further characterised. Inverse PCR was used to amplify a 1.5 kb fragment of plant DNA flanking the single-copy T-DNA insertion in this line. With the exception of a 249 bp highly repetitive element, this sequence is present as a single copy in the tobacco genome, and is not homologous to any previously characterised DNA sequences. Sequence analysis revealed the presence of several motifs that may be involved in transcriptional regulation. Transgenic tobacco plants transformed with a transcriptional fusion of this putative promoter sequence to the beta-glucuronidase (uidA) reporter gene, showed GUS activity confined to the shoot tip and mature pollen. This promoter may be useful to direct the expression of genes controlling the transition to flowering, or genes to reduce losses due to pests and stresses damaging plant apical meristems.

Structure of the tegument and ectocommensal microorganisms of Gyliauchen nahaensis (Digenea : Gyliauchenidae), an inhabitant of herbivorous fish of the Great Barrier Reef, Australia

The ultrastructure of the tegument and tegument-associated microorganisms of the gyliauchenid digenean Gyliauchen nahaensis is described by transmission and scanning electron microscopy. The tegument is devoid of surface spines and is characterized by a moderately folded apical membrane, abundant vesicles, basal mitochondria, a folded basal plasma membrane, and a thick basal matrix. Microorganisms form a dense biofilm on the tegument of the posterodorsal surface and the excretory papilla. At least 7 microbial morphotypes were identified, including eubacteria, spirochaetes, and nanobacteria.

Hypoechinorhynchus robustus sp n. from Notolabrus parilus (Labridae) from Western Australia with a discussion on the validity of the hypoechinorhynchidae (Acanthocephala : Palaeacanthocephala)

Hypoechinorhynchus robustus sp. n. is described from Notolabrus parilus (Richardson) (Labridae) from Pt Peron, Western Australia. It has a proboscis with 30 hooks arranged in ten longitudinal rows: 5 rows of a small apical spine, a large anterior hook and a small posterior spine, 5 rows of a large anterior hook, a middle spine and a posterior spine. The new species is distinguished from other species of the genus by having a set of 5 small apical spines anterior to the large hooks on the proboscis, by having lemnisci that barely extend beyond the proboscis receptacle and testes which are more adjacent than tandem. H. robustus also has robust trunk spines anteriorly. Re-examination of Hypoechinorhynchus alaeopis Yamaguti, 1939 (type species) revealed trunk spines that had been overlooked previously. The Hypoechinorhynchidae is made a junior synonym of Arhythmacanthidae because there is considerable overlap between the two family diagnoses, particularly in that both families have a proboscis armature that changes abruptly from small basal spines to large apical (or subapical if present) hooks. The genus Hypoechinorhynchus is placed in the subfamily Arhythmacanthinae because it has trunk spines and a spherical proboscis with few hooks (relative to other arhythmacanthid genera). It is also proposed that Heterosentis magellanicus (Szidat, 1950) be returned to the genus Hypoechinorhynchus since it was transferred to Heterosentis primarily because it had trunk spines. The other hypoechinorhynchid genus contained only Bolborhynchoides exiguus (Achmerov et Dombrowskaja-Achmerova, 1941) Achmerov, 1959 and is relegated to incertae sedis.

Neuromuscular-skeletal constraints upon the dynamics of unimanual and bimanual coordination

In the first of three experiments, 11 participants generated pronation and supination movements of the forearm, in time with an auditory metronome. The metronome frequency was increased in eight steps (0.25 Hz) from a base frequency of 1.75 Hz. On alternating trials, participants were required to coordinate either maximum pronation or maximum supination with each beat of the metronome. In each block of trials, the axis of rotation was either coincident with the long axis of the forearm, above this axis, or below this axis. The stability of the pronate-on-the-beat pattern, as indexed by the number of pattern changes, and the time of onset of pattern change, was greatest when the axis of rotation of the movement was below the long axis of the forearm. In contrast, the stability of the supinate-on-the-beat pattern was greatest when the axis of rotation of the movement was above the long axis of the forearm. In a second experiment, we examined how changes in the position of the axis of rotation alter the activation patterns of muscles that contribute to pronation and supination of the forearm. Variations in the relative dominance of the pronation and supination phases of the movement cycle across conditions were accounted for primarily by changes in the activation profile of flexor carpi radialis (FCR) and extensor carpi radialis longus (ECR). In the Final experiment we examined how these constraints impact upon the stability of bimanual coordination. Thirty-two participants were assigned at random to one of four conditions, each of which combined an axis of rotation configuration (bottom or top) for each limb. The participants generated both inphase (both limbs pronating simultaneously, and supinating simultaneously) and antiphase (left limb pronating and right limb supinating simultaneously, and vice versa) patterns of coordination. When the position of the axis of rotation was equivalent for the left and the right limb, transitions from antiphase to inphase patterns of coordination were Frequently observed. In marked contrast, when the position of the axis of rotation for the left and right limb was contradistinct, transitions From inphase to antiphase patterns of coordination occurred. The results demonstrated that when movements are performed in an appropriate mechanical context, inphase patterns of coordination are less stable than antiphase patterns.

Beyond prejudice as simple antipathy: Hostile and benevolent sexism across cultures

The authors argue that complementary hostile and benevolent components of sexism exist across cultures. Male dominance creates hostile sexism IHS), but men's dependence on women fosters benevolent sexism (BS)-subjectively positive attitudes that put women on a pedestal but reinforce their subordination. Research with 15,000 men and women in 19 nations showed that (a) HS and BS are coherent constructs that correlate positively across nations, but (b) HS predicts the ascription of negative and BS the ascription of positive traits to women, (c) relative to men, women are more likely to reject HS than BS, especially when overall levels of sexism in a culture are high, and (d) national averages on BS and HS predict gender inequality across nations. These results challenge prevailing notions of prejudice as an antipathy in that BS tan affectionate, patronizing ideology) reflects inequality and is a cross-culturally pervasive complement to HS.

Morphological and electrophysiological properties of principal neurons in the rat lateral amygdala in vitro

In this study, we characterize the electrophysiological and morphological properties of spiny principal neurons in the rat lateral amygdala using whole cell recordings in acute brain slices. These neurons exhibited a range of firing properties in response to prolonged current injection. Responses varied from cells that showed full spike frequency adaptation, spiking three to five times, to those that showed no adaptation. The differences in firing patterns were largely explained by the amplitude of the afterhyperpolarization (AHP) that followed spike trains. Cells that showed full spike frequency adaptation had large amplitude slow AHPs, whereas cells that discharged tonically had slow AHPs of much smaller amplitude. During spike trains, all cells showed a similar broadening of their action potentials. Biocytin-filled neurons showed a range of pyramidal-like morphologies, differed in dendritic complexity, had spiny dendrites, and differed in the degree to which they clearly exhibited apical versus basal dendrites. Quantitative analysis revealed no association between cell morphology and firing properties. We conclude that the discharge properties of neurons in the lateral nucleus, in response to somatic current injections, are determined by the differential distribution of ionic conductances rather than through mechanisms that rely on cell morphology.

Autonomic activity during human sleep as a function of time and sleep stage

While there is a developing understanding of the influence of sleep on cardiovascular autonomic activity in humans, there remain unresolved issues. In particular, the effect of time within the sleep period, independent of sleep stage, has not been investigated. Further, the influence of sleep on central sympathetic nervous system (SNS) activity is uncertain because results using the major method applicable to humans, the low frequency (LF) component of heart rate Variability (HRV), have been contradictory, and because the method itself is open to criticism. Sleep and cardiac activity were measured in 14 young healthy subjects on three nights. Data was analysed in 2-min epochs. All epochs meeting specified criteria were identified, beginning 2 h before, until 7 h after, sleep onset. Epoch values were allocated to 30-min bins and during sleep were also classified into stage 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep. The measures of cardiac activity were heart irate (HR), blood pressure (BP), high frequency (HF) and LF components of HRV and pre-ejection period (PEP). During non-rapid eye movement (NREM) sleep autonomic balance shifted from sympathetic to parasympathetic dominance, although this appeared to be more because of a shift in parasympathetic nervous system (PNS) activity. Autonomic balance during REM was in general similar to wakefulness. For BP and the HF and LF components the change occurred abruptly at sleep onset and was then constant over time within each stage of sleep, indicating that any change in autonomic balance over the sleep period is a consequence of the changing distribution of sleep stages. Two variables, HR and PEP, did show time effects reflecting a circadian influence over HR and perhaps time asleep affecting PEP. While both the LF component and PEP showed changes consistent with reduced sympathetic tone during sleep, their pattern of change over time differed.

Nuclear calcium signaling evoked by cholinergic stimulation in hippocampal CA1 pyramidal neurons

The cholinergic system is thought to play an important role in hippocampal-dependent learning and memory. However, the mechanism of action of the cholinergic system in these actions in not well understood. Here we examined the effect of muscarinic receptor stimulation in hippocampal CA1 pyramidal neurons using whole-cell recordings in acute brain slices coupled with high-speed imaging of intracellular calcium. Activation of muscarinic acetylcholine receptors by synaptic stimulation of cholinergic afferents or application of muscarinic agonist in CA1 pyramidal neurons evoked a focal rise in free calcium in the apical dendrite that propagated as a wave into the soma and invaded the nucleus. The calcium rise to a single action potential was reduced during muscarinic stimulation. Conversely, the calcium rise during trains of action potentials was enhanced during muscarinic stimulation. The enhancement of free intracellular calcium was most pronounced in the soma and nuclear regions. In many cases, the calcium rise was distinguished by a clear inflection in the rising phase of the calcium transient, indicative of a regenerative response. Both calcium waves and the amplification of action potential-induced calcium transients were blocked the emptying of intracellular calcium stores or by antagonism of inositol 1,4,5-trisphosphate receptors with heparin or caffeine. Ryanodine receptors were not essential for the calcium waves or enhancement of calcium responses. Because rises in nuclear calcium are known to initiate the transcription of novel genes, we suggest that these actions of cholinergic stimulation may underlie its effects on learning and memory.

To fix or not to fix: The role of 2-phenoxyethanol in rabbit, Oryctolagus cuniculus, chin gland secretion

The European rabbit (Oryctolagus cuniculus) uses the secretion of the chin gland to maintain dominance hierarchies in the wild. Recent work has investigated changes in the secretion when social status is manipulated in the rabbit. When a rabbit becomes dominant, a new compound appears in his secretion, 2-phenoxyethanol. This compound is used as a fixative in the perfume industry. This study investigates whether the compound performs a similar function in the secretion of the rabbit. 2-Phenoxyethanol is not detected olfactorially by rabbits, and slows the release rate of some of the compounds that occur naturally in rabbit chin gland secretion. We suggest that when a rabbit becomes dominant, he adds a fixative to his secretion so that his scent will persist in the environment and not dissipate. He will thus come to dominate the olfactory environment, in much the same way as he does the physical environment.

Anogenital gland secretions of Lemur catta and Propithecus verreauxi coquereli: A preliminary chemical examination

Although prosimians are greatly olfaction-oriented, little is known about the specifics of how they use scent to communicate. In this preliminary study we attempted to delineate intra- and interspecific differences among the anogenital gland secretions of two lemur species (Lemur catta and Propithecus verreauxi coquereli) using gas chromatography-mass spectrometry (GC-MS). The results indicate that the two species are discernible through scent. Furthermore, we were able to identify reproductive status using this technique. The anogenital secretions of the different sexes in L. catta, though perhaps not P. v. coquereli, are chemically distinguishable. Given this information, it appears that at least some lemur species can use scent marks to determine species, sex, and reproductive status. (C) 2004 Wiley-Liss, Inc.

The look of royalty: visual and odour signals of reproductive status in a paper wasp

Reproductive conflicts within animal societies occur when all females can potentially reproduce. In social insects, these conflicts are regulated largely by behaviour and chemical signalling. There is evidence that presence of signals, which provide direct information about the quality of the reproductive females would increase the fitness of all parties. In this study, we present an association between visual and chemical signals in the paper wasp Polistes satan. Our results showed that in nest-founding phase colonies, variation of visual signals is linked to relative fertility, while chemical signals are related to dominance status. In addition, experiments revealed that higher hierarchical positions were occupied by subordinates with distinct proportions of cuticular hydrocarbons and distinct visual marks. Therefore, these wasps present cues that convey reliable information of their reproductive status.

Na,K-ATPase activity and epithelial interfaces in gills of the freshwater shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae)

Diadromous freshwater shrimps are exposed to brackish water both as an obligatory part of their larval life cycle and during adult reproductive migration; their well-developed osmoregulatory ability is crucial to survival in such habitats. This study examines gill microsomal Na,K-ATPase (K-phosphatase activity) kinetics and protein profiles in the freshwater shrimp Macrobrachium amazonicum when in fresh water and after 10-days of acclimation to brackish water (21 parts per thousand salinity), as well as potential routes of Na(+) uptake across the gill epithelium in fresh water. On acclimation, K-phosphatase activity decreases 2.5-fold, Na,K-ATPase alpha-subunit expression declines, total protein expression pattern is markedly altered, and enzyme activity becomes redistributed into different density membrane fractions, possibly reflecting altered vesicle trafficking between the plasma membrane and intracellular compartments. Ultrastructural analysis reveals an intimately coupled pillar cell-septal cell architecture and shows that the cell membrane interfaces between the external medium and the hemolymph are greatly augmented by apical pillar cell evaginations and septal cell inviginations, respectively. These findings ire discussed regarding the putative movement of Na(+) across the pillar cell interfaces and into the hemolymph via the septal cells, powered by the Na,K-ATPase located in their invaginations. (C) 2008 Elsevier Inc. All rights reserved.

Differential adjustment in gill Na(+)/K(+)- and V-ATPase activities and transporter mRNA expression during osmoregulatory acclimation in the cinnamon shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae)

We evaluate osmotic and chloride (Cl(-)) regulatory capability in the diadromous shrimp Macrobrachium amazonicum, and the accompanying alterations in hemolymph osmolality and [Cl(-)], gill Na(+)/K(+)-ATPase activity, and expression of gill Na(+)/K(+)-ATPase alpha-subunit and V-ATPase B subunit mRNA during salinity (S) acclimation. We also characterize V-ATPase kinetics and the organization of transport-related membrane systems in the gill epithelium. Macrobrachium amazonicum strongly hyper-regulates hemolymph osmolality and [Cl(-)] in freshwater and in salinities up to 25 parts per thousand S. During a 10-day acclimation period to 25 parts per thousand S, hemolymph became isosmotic and hypo-chloremic after 5 days, [Cl(-)] alone remaining hyporegulated thereafter. Gill Na(+)/K(+)-ATPase alpha-subunit mRNA expression increased 6.5 times initial values after 1 h, then decreased to 3 to 4 times initial values by 24 h and to 1.5 times initial values after 10 days at 25 parts per thousand S. This increased expression was accompanied by a sharp decrease at 5 h then recovery of initial Na(+)/K(+)-ATPase activity within 24 h, declining again after 5 days, which suggests transient Cl(-) secretion. V-ATPase B-subunit mRNA expression increased 1.5-fold within 1 h, then reduced sharply to 0.3 times initial values by 5 h, and remained unchanged for the remainder of the 10-day period. V-ATPase activity dropped sharply and was negligible after a 10-day acclimation period to 21 parts per thousand S, revealing a marked downregulation of ion uptake mechanisms. The gill epithelium consists of thick, apical pillar cell flanges, the perikarya of which are coupled to an intralamellar septum. These two cell types respectively exhibit extensive apical evaginations and deep membrane invaginations, both of which are associated with numerous mitochondria, characterizing an ion transporting epithelium. These changes in Na(+)/K(+)- and V-ATPase activities and in mRNA expression during salinity acclimation appear to underpin ion uptake and Cl(-) secretion by the palaemonid shrimp gill.