Variable but not random: temporal pattern coding in a songbird brain area necessary for song modification.

Practice of a complex motor gesture involves motor exploration to attain a better match to target, but little is known about the neural code for such exploration. We examine spiking in a premotor area of the songbird brain critical for song modification and quantify correlations between spiking and time in the motor sequence. While isolated spikes code for time in song during performance of song to a female bird, extended strings of spiking and silence, particularly bursts, code for time in song during undirected (solo) singing, or "practice." Bursts code for particular times in song with more information than individual spikes, and this spike-spike synergy is significantly higher during undirected singing. The observed pattern information cannot be accounted for by a Poisson model with a matched time-varying rate, indicating that the precise timing of spikes in both bursts in undirected singing and isolated spikes in directed singing code for song with a temporal code. Temporal coding during practice supports the hypothesis that lateral magnocellular nucleus of the anterior nidopallium neurons actively guide song modification at local instances in time.NEW & NOTEWORTHY This paper shows that bursts of spikes in the songbird brain during practice carry information about the output motor pattern. The brain's code for song changes with social context, in performance versus practice. Synergistic combinations of spiking and silence code for time in the bird's song. This is one of the first uses of information theory to quantify neural information about a motor output. This activity may guide changes to the song.

Assessment of rainwater harvesting systems at a university in Taipei.

Rainwater harvesting systems (RWHSs), a pilot-scale one (PSR) and a full-scale one (FSR), at a university campus in Taipei were assessed. Characteristics of harvested rainwater were analyzed, including pH, electrical conductivity (EC), turbidity, alkalinity, dissolved organic carbon (DOC), total coliform (TC), concentration of 14 metals (Al, Ca, K, Mg, Na, Cu, Fe, Mn, V, Zn, Cd, Cr, Pb and Ni) and concentration of 3 anions (Cl(-), SO(4)(2-) and NO(3)(-)). Rainwater in the FSR had pH in the neutral range and high alkalinity, whereas those of the PSR were acidic and with low buffer ability because of different catchment materials. Median concentrations of 14 metals from two RWHSs were low, except for Na, Ca, K and Mg. Anions, including Cl(-), NO(3)(-), and SO(4)(2-) showed much higher concentration in winter, indicating the influences of marine source and northeast monsoon. Effects of 14-day storage were examined and it was found that pH did not change, while EC, turbidity and DOC slightly decreased. Concentrations of anions and metals were stable, and TC counts of harvested rainwater increased in the beginning, and then declined with storage time. During antecedent dry days, total suspended particulates (TSPs) were collected and their dissolution was examined. Preliminary correlation of wet and dry depositions with rainwater quality was explored.

Variability in action: Contributions of a songbird cortical-basal ganglia circuit to vocal motor learning and control.

Many motor behaviors, from walking to speaking, are acquired through experience, in particular, through trial-and-error learning. The acquisition and maintenance of such motor behaviors in a wide range of species, including humans, appear to depend on cortical-basal ganglia circuits. In this review, we discuss recent studies in songbirds that have been pivotal in informing our current understanding of motor learning and cortical-basal ganglia function. Songbirds are important ethological model systems for the study of motor learning because young songbirds naturally develop and refine their songs through trial-and-error learning. In addition, reinforcement mechanisms are hypothesized to be important for the maintenance and plasticity of structured adult song. Computational and experimental studies highlight the importance of vocal motor variability as the substrate upon which reinforcement mechanisms could operate to shape developing song and to maintain adult song. Recent studies in songbirds indicate that this vocal motor variability is actively generated and modulated by a highly specialized cortical-basal ganglia circuit evolved for a single behavior, song. We argue that these and other recent findings illustrate how the tight association between a specialized neural circuit and a natural behavior make songbirds a unique and powerful model in which to investigate the neural substrates of motor learning and plasticity.

Antifreeze glycoproteins: relationship between molecular weight, thermal hysteresis and the inhibition of leakage from liposomes during thermotropic phase transition.

Antifreeze glycoproteins (AFGP) were isolated and purified from the blood plasma of rock cod (Gadus ogac), using DEAE-Bio-gel ion exchange chromatography, followed by high performance liquid chromatography (HPLC). The purified proteins were analyzed using polyacrylamide gel electrophoresis (PAGE), and electrospray mass spectrometry. The results indicated that rock cod synthesize seven size classes of glycoproteins, ranging from 2.6 to 24 kDa, with each size class containing multiple isoforms. Antifreeze activity, as determined by thermal hysteresis, indicated that the AFGP could be separated into two groups, with the larger size classes (molecular mass>13 kDa) having approximately 3-4 times the activity of the smaller, proline containing, size classes (molecular mass<10 kDa). All of the AFGP size classes prevented leakage from dielaidoylphosphatidylcholine (DEPC) liposomes as they were cooled through their phase transition temperature, with the larger size classes being approximately 4 times as effective as the smaller ones. It is hypothesized that AFGP prevent liposomes from leaking as they pass through the phase transition temperature by binding to the phospholipid membrane.

Comparison of major aeroallergens in Taipei and Kin-Men.

Ragweed pollen is an important aeroallergen in the USA, however, its role in the pathogenesis of allergic airway diseases in Taiwan has not been reported. Recently, a dramatic increase in patients with allergic rhinitis was noted in Kin-Men. Most patients had characteristic seasonal variation with the symptoms waxing in August and waning in November, which correlated with the pollen season of ragweed. The aim of this study was to clarify the role of ragweed pollen in the pathogenesis of allergic airway disease in Taipei and Kin-Men. Ragweed pollen from Kin-Men was collected, extracted, and resuspended in phosphate-buffered saline for a skin prick test. Greer ragweed pollen extract was used as a control. Serum from patients with a positive skin test was investigated for the ragweed pollen-specific immunoglobulin E (IgE). The IgE-binding components in the ragweed pollen were determined using immunoblot analysis. Of 101 patients from Kin-Men, 79 responded to ragweed. Only eight of 117 patients from Taipei responded to the same allergen. The titers of ragweed-specific IgE antibodies in the sera from Kin-Men were much higher than in the sera from Taipei. The response rate to the most common indoor allergen, Dermatophagoides pteronyssinus, was much lower in Kin-Men than in Taipei (25.7% and 90.6%, respectively). Thus, there were different aeroallergens in Kin-Men and Taipei. Having what was in both cases a Chinese population affected by different allergens indicates that environmental allergens may play an important role in the pathogenesis of allergic airway diseases. These results may also serve as a reference for the prophylaxis of allergic rhinitis in Kin-Men.

Hypersensitivity of bronchial asthmatics to cockroach in Taiwan. comparative study between American and German cockroaches.

This study was performed to test the hypersensitivity of asthmatics to American and German cockroaches, which are both common in Taiwan. A total of 236 asthmatic patients received skin prick test using allergen extracts from both American and German cockroaches, and 596 sera from asthmatic patients were analyzed for their specific IgE against German cockroach extract. The results of skin test showed that 39.4 and 36.4% asthmatic patients were hypersensitive to American and German cockroaches. Fifteen among 236 patients were only allergic to American cockroaches and 8 were only allergic to German cockroaches. Using the Pharmacia CAP system, 36% of the sera were found to contain the specific IgE to German cockroach extract. Eighty-nine sera positive for German cockroach extract were then tested for their reactivity to American cockroach extract using the fluoroallergosorbent test (FAST). Sixty among 89 (68%) of their sera contained American cockroach-specific IgE. The correlation coefficient between both parameters was r = 0.45. Immunoblot and immunoblot inhibition studies were performed to analyze the IgE-binding components and the cross-reactivity between American and German cockroaches. The results showed that there are different IgE-binding components between American and German cockroaches. Sera containing specific IgE to both species of cockroach were absorbed with both species of cockroach extracts. The specific IgE to German cockroaches can be absorbed by American cockroach extract in all selected sera and the specific IgE to American cockroaches can only partially be absorbed by German cockroaches. The nonabsorbed allergens in American cockroaches had molecular weights of 33 and 50 kD. In conclusion, one-third of the asthmatic population tested was allergic to cockroaches. Although most cockroach-hypersensitive patients were allergic to both American and German cockroaches, more asthmatic patients were allergic to American cockroaches in Taiwan. The use of non-crossreacting allergen in detecting American cockroach-specific IgE might be important not only for the diagnosis and treatment of cockroach hypersensitivity in asthmatics but also for the differentiation between German and American cockroach hypersensitivity.

The respiratory burst activity of activated eosinophils in atopic asthmatics.

Although activated eosinophils in peribronchial tissue and peripheral blood are increased in patients with asthma, the mechanisms contributing to their presence and causing airway hyperreactivity are not well established. Recently, the respiratory burst activity on activated eosinophils can be evaluated by dual staining with monoclonal antibody EG2 and 2,7-dichlorofluorescein diacetate, which can be analyzed with the FACS analyzer. The severity of allergy and airway hyperreactivity can be evaluated by allergen-specific IgE and airway hyperresponsiveness to methacholine. In this study we evaluated the cell numbers with respiratory burst activity on activated eosinophils and correlated these cell numbers with the allergen-specific IgE and airway hyperresponsiveness to methacholine. Results showed that the cell number with respiratory burst activity of activated eosinophils was increased in those patients with more hyperresponsiveness to methacholine and correlated with PD20 of methacholine with r = -0.643 and p = 0.01. The number of activated eosinophils was also correlated with allergen-specific IgE with r = 0.641 and p = 0.025. There were increased cell numbers of activated eosinophils (EG2(+)/PMN) and cells with respiratory burst activity (DCF+EG2(+)/PMN) in the unstable asthmatic patients when compared to those of stable asthmatic patients. These results suggest that there is in vivo activation of eosinophils in the asthmatic patients, especially in the unstable patients and patients who have airways more hyperreponsive to methacholine. We concluded that the cell numbers with respiratory burst activity of activated eosinophils cannot only reflect the airway hyperresponsiveness but also the disease severity of asthmatic patients.

Geometric constraints for the design of diffusing-wave spectroscopy experiments.

Diffusing-wave spectroscopy (DWS) experiments require the choice of suitable sample geometry. We study sample geometries for transmission experiments by performing DWS measurements on a variable thickness cell. The data reveal that DWS works well, giving consistent answers to within 5% when the cell is more than 10 random walk step lengths thick, and that the input geometry is less significant when sample cells are immersed in water than when they are surrounded by air. Further, we see that the applicability of the diffusion approximation depends on the anisotropy of individual scattering events.

Differential amplification of antifreeze protein genes in the pleuronectinae.

The organization of antifreeze protein (AFP) genes in the yellowtail flounder was investigated by Southern blotting and the characterization of clones from a genomic library. This flounder, like the closely related winter flounder, has a set of 10-12 linked but irregularly spaced AFP genes. However, it lacks the tandemly amplified set of 20 such genes that are present in the winter flounder. DNA sequence analysis of a tandemly repeated gene from winter flounder showed that it can code for one of the two most abundant AFP components in the serum. Consistent with this higher AFP gene dosage, the peak serum AFP level in midwinter was 9 mg/ml in the winter flounder and only 4 mg/ml in the yellowtail flounder. A recent amplification of the AFP gene in the winter flounder lineage might be responsible for the higher serum AFP levels in this fish. This increase in gene dosage might have helped the winter flounder colonize the ice-laden, shallow-water niche that it currently occupies along the east coast of North America. Genomic Southern blotting of two other righteye flounders, the smooth flounder and the American plaice, illustrates another example of a differential amplification of AFP genes that correlates with a species' exposure to ice.

Stress and dominance in a social fish.

Many aspects of reproductive physiology are subject to regulation by social interactions. These include changes in neural and physiological substrates of reproduction. How can social behavior produce such changes? In experiments reported here, we manipulated the social settings of teleost fish and measured the effect (1) on stress response as reflected in cortisol production, (2) on reproductive potential as measured in production of the signaling peptide, gonadotropin-releasing hormone, and (3) on reproductive function measured in gonad size. Our results reveal that the level of the stress hormone cortisol depends critically on both the social and reproductive status of an individual fish and on the stability of its social situation. Moreover, the reproductive capacity of an individual fish depends on these same variables. These results show that social encounters within particular social contexts have a profound effect on the stress levels as well as on reproductive competence. Social behavior may lead to changes in reproductive state through integration of cortisol changes in time. Thus, information available from the stress pathway may provide socially relevant signals to produce neural change.

Antifreeze proteins in the urine of marine fish.

Several species of marine teleosts have evolved blood plasma antifreeze polypeptides which enable them to survive in ice-laden seawater. Four distinct antifreeze protein classes differing in carbohydrate content, amino acid composition, protein sequence and secondary structure are currently known. Although all of these antifreezes are relatively small (2.6-33 kd) it was generally thought that they were excluded from the urine by a variety of glomerular mechanisms. In the present study antifreeze polypeptides were found in the bladder urine of winter flounder (Pseudopleuronectes americanus), sea raven (Hemitripterus americanus), ocean pout (Macrozoarces americanus) and Atlantic cod (Gadus morhua). Since the plasma of each of these fish contains a different antifreeze class it would appear that all four classes of antifreeze can enter the urine. The major antifreeze components in the urine of winter flounder were found to be identical to the major plasma components in terms of high performance liquid chromatography retention times and amino acid composition. It is concluded that plasma antifreeze peptides need not be chemically modified before they can enter the urine.

Structures of shorthorn sculpin antifreeze polypeptides.

The amino acid sequences of the two major antifreeze polypeptides (AFP) from the shorthorn sculpin have been determined using an automatic protein sequencer and enzymic digestion. These two polypeptides, SS-3 and SS-8, consist of 33 and 45 amino acid residues respectively. The N-terminal methionyl residue is blocked in both the polypeptides. When aligned for maximum structural similarity these two AFP are 80% homologous, and there appears a deletion of 12 amino acid residues at the N-terminal portion of SS-3. Like the winter flounder AFP, both the sculpin AFP also contain the 11-amino-acid repeat sequences. The secondary structure of the sculpin AFP is mainly alpha-helical as deduced from circular dichroic spectral data. The helical content of SS-8 is high (73%), while that of SS-3 is moderate (about 45%). The latter exhibits a relatively weak antifreeze activity. Removal of the blocked N-terminal residue in SS-8 did not alter the helical content significantly but did reduce the antifreeze activity. Helical contents of proteolytically generated fragments of AFP are much lower, and they are devoid of activity. The alpha-helix in the SS-8 component is seen to be amphiphilic in character. The relevance of this feature to the mechanism of the antifreeze action is briefly discussed.

Small granule-containing (SGC) cells in the hamster adrenal medulla.

In addition to adrenalin (A)- and noradrenaline (NA)-containing cells in the hamster adrenal medulla, a third type of small granule-containing (SGC) cells was identified. These cells were characterized by their small size (about 15 microns in diameter) and location adjacent to A-cells. Numerous pleomorphic dense-cored cytoplasmic granules (306 +/- 44.5 nm x 204.5 +/- 58.3 nm, mean +/- standard error) were present in their cytoplasm. The ultrastructure of these granules were similar to that of NA-containing granules but smaller in size. The granular inclusions of the granules were moderate to high in electrol density. The cytoplasm of the SGC cells contained short profiles of rough endoplasmic reticulum and some free ribosomes.

Ultrastructure, ZIO-staining and chromaffinity of gerbil pinealocytes.

The ultrastructure and cytochemistry of the gerbil pineal gland were studied by the conventional electron microscopy, zinc iodide-osmium tetroxide (ZIO) staining and chromaffin reaction. Conventional electron microscopy revealed that the ultrastructure of gerbil pinealocytes are similar to other rodents, i.e., irregular cell contour with numerous cytoplasmic processes, round or oval nucleus and prominent nucleoli, elongated mitochondria with flattened and tubular cristae and dense matrix, well-developed Golgi apparatus and its associated structures, abundant elements of endoplasmic reticulum--both smooth and rough varieties, and bundles of microfilament and microtubule in the cytoplasm. Some pinealocyte processes contain numerous small clear and "slightly coated" vesicles. Numerous profiles of varicosities containing small dense-cored and clear vesicles were frequently encountered. After ZIO treatment, ZIO staining was preferentially localized in the cytoplasm of some, but not all, of the gerbil pinealocytes. Numerous small clear vesicles (30-50 nm in diameter) in the process of the pinealocytes or in the varicosities of the nerve fibers showed strong ZIO-philia. After chromaffin reaction treatment, the number and electron density of small clear and dense-cored vesicles in the profiles of nerve varicosities increased and this indicates that some of the small clear and dense-cored vesicles in the varicosities are reactive. It is thus concluded that (1) the vesicles in the pinealocytes may be rich in cystine and/or cysteine and possibly the organelle is involved in the sequestering calcium ion during the calcification of the pineal concretions, and (2) the small dense-cored and clear vesicles in the nerve fibers in the gerbil pineal parenchyma may contain both serotonin and primary biogenic amines.

Ethanol and acetaldehyde metabolism in chinese with different aldehyde dehydrogenase-2 genotypes.

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the major enzymes responsible for ethanol metabolism in humans. Both enzymes exhibit genetic polymorphisms among racial populations. About half of the Chinese population lack mitochondrial ALDH2 activity and such a deficiency has been believed to be a negative risk factor for the development of alcoholism. To assess ethanol and acetaldehyde metabolism in Chinese with different ALDH2 genotypes, we genotyped 273 male adults at the ADH2, ADH3, and ALDH2 loci by using polymerase chain reaction-directed mutagenesis and restriction fragment length polymorphisms. Of the 143 individuals homozygous for both the ADH2*2 and the ADH3*1 alleles, 80, 55, and 8 were identified as ALDH2*1/*1, ALDH2*1/*2, and ALDH2*/*2, respectively. Five each from the above three ALDH2 genotypic subjects underwent alcohol elimination testing. Blood ethanol and acetaldehyde levels were determined at various times up to 130 min after intaking a low dose of ethanol (0.2 g/kg body weight) by using head-space gas chromatography and high-performance liquid chromatography with fluorescence detection, respectively. The mutant homozygotes of ALDH2*2/*2 and the heterozygotes exhibited significantly higher peak acetaldehyde concentrations and also greater areas under the blood concentrations-time curve (AUC) than did the normal homozygotes of ALDH2*1/*1, with the mutant homozygotes both being the largest. The mutant homozygotes displayed significantly higher peak ethanol levels and AUC compared to the normal homozygotes. Of the 17 subjective feeling items tested, palpitation, facial warming, effects of alcohol, and dizziness were found to be most pronounced among the mutant homozygotes.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentially and developmentally regulated expression of three rice sucrose synthase genes.

The spatial and temporal distribution of sucrose synthase (RSuS) in rice (Oryza sativa L.) was studied by Western and immunohistochemical analyses using the monospecific antibodies for three RSuS isoforms. In leaf tissues, RSuS1 was localized in the mesophyll while RSuS2 was in the phloem in addition to the mesophyll. In the roots, only RSuS1 was found in the phloem. No RSuS3 could be detected in any parts of etiolated seedlings. The expression of each RSus gene is closely linked to the seed development. RSuS1 was present in the aleurone layers of developing seeds, and at a low level in endosperm cells. RSuS2 was evenly distributed in seed tissues other than the endosperm. RSuS3 was localized predominantly in the endosperm cells. The tissue specific localizations of the three gene products suggest that RSuS1 plays a role in sugar transport into endosperm cells where the reaction catalyzed by RSuS3 provides the precursor of starch synthesis. RSus2, which is ubiquitously expressed, may play a housekeeping role.