Acoustic parameters of dog barks carry emotional information for humans

In an earlier study, we found that humans were able to categorize dog barks correctly, which were recorded in various situations. The acoustic parameters, like tonality, pitch and inter-bark time intervals, seemed to have a strong effect on how human listeners described the emotionality of these dog vocalisations. In this study, we investigated if the effect of the acoustic parameters of the dog bark is the same on the human listeners as we would expect it from studies in other mammalian species (for example, low, hoarse sounds indicating aggression; high pitched, tonal sounds indicating subordinance/fear). People with different experience with dogs were asked to describe the emotional content of several artificially assembled bark sequences on the basis of five emotional states (aggressiveness, fear, despair, playfulness, happiness). The selection of the barks was based on low, medium and high values of tonality and peak frequency. For assembling artificial bark sequences, we used short, middle or long inter-bark intervals. We found that humans with different levels of experience with dogs described the emotional content of the bark sequences quite similarly, and the extent of previous experience with the given breed (Mudi), or with dogs in general, did not cause characteristic differences in the emotionality scores. The scoring of the emotional content of the bark sequences was in accordance with the so-called Morton's structural–acoustic rules. Thus, low pitched barks were described as aggressive, and tonal and high pitched barks were scored as either fearful or desperate, but always without aggressiveness. In general, tonality of the bark sequence had much less effect than the pitch of the sounds. We found also that the inter-bark intervals had a strong effect on the emotionality of dog barks for the human listeners: bark sequences with short inter-bark intervals were scored as aggressive, but bark sequences with longer inter-bark intervals were scored with low values of aggression. High pitched bark sequences with long inter-bark intervals were considered happy and playful, independently from their tonality. These findings show that dog barks function as predicted by the structural–motivational rules developed for acoustic signals in other species, suggesting that dog barks may present a functional system for communication at least in the dog–human relationship. In sum it seems that many types of different emotions can be expressed with the variation of at least three acoustic parameters.     

Present distribution of the genus Elodea in the Alsatian Upper Rhine floodplain (France) with a special focus on the expansion of Elodea nuttallii St. John during recent decades

Three species of Elodea (Elodea canadensis Michaux, E. nuttallii St John and E. ernstiae St John) have colonized Europe from the American continent. All three arrived in the Alsatian Rhine floodplain (north-eastern France) soon after their arrival in Europe, i.e. in the mid-19th century for E. canadensis, and in the mid-20th century for E. nuttallii and E. ernstiae. The paper investigates the present distribution of Elodea spp. in the floodplain by quantifying the species’ respective occurrences and by describing their habitats. The study further focuses on E. nuttallii which is presently colonizing other parts of Europe. It analyses whether it has continued to expand in the Alsatian Rhine floodplain during recent decades, and it checks whether changes in the abundance of E. nuttallii have had an impact on species richness of water plant communities. E.␣nuttallii has been found to be at present one of the most dominant and most frequent aquatic plant species in the study sector, while E. canadensis and E. ernstiae are less abundant. The species’ distributions differ with regard to water chemistry and water temperature: E. canadensis occurs in oligo-mesotrophic, rather stenothermic habitats, whereas E. nuttallii and E. ernstiae can be encountered in meso- to eutrophic sites with little or no arrival of stenothermic ground water. By comparing successive vegetation relevés from the same sites the study revealed further that the distribution of E. nuttallii has been stable in recent decades, despite local fluctuations in abundance. No relationship could be established between those fluctuations and changes in species richness or type of local plant communities. The sum of the results suggests that the expansion of E. nuttallii in the Alsatian Rhine floodplain had been completed prior to the study period. The species’ present distribution in the study sector as well as its position in local plant communities might therefore be considered a model for what can be expected to happen in areas where E.␣nuttallii has only recently arrived.     

3(10)-helices in proteins are parahelices

The 3(10)-helix is characterized by having at least two consecutive hydrogen bonds between the main-chain carbonyl oxygen of residue i and the main-chain amide hydrogen of residue i + 3. The helical parameters--pitch, residues per turn, radius, and root mean square deviation (rmsd) from the best-fit helix--were determined by using the HELFIT program. All 3(10)-helices were classified as regular or irregular based on rmsd/(N - 1)1/2 where N is the helix length. For both there are systematic, position-specific shifts in the backbone dihedral angles. The average phi, psi shift systematically from approximately -58 degrees, approximately -32 degrees to approximately -90 degrees, approximately -4 degrees for helices 5, 6, and 7 residues long. The same general pattern is seen for helices, N = 8 and 9; however, in N = 9, the trend is repeated with residues 6, 7, and 8 approximately repeating the phi, psi of residues 2, 3, and 4. The residues per turn and radius of regular 3(10)-helices decrease with increasing length of helix, while the helix pitch and rise per residue increase. That is, regular 3(10)-helices become thinner and longer as N increases from 5 to 8. The fraction of regular 3(10)-helices decreases linearly with helix length. All longer helices, N > or = 9 are irregular. Energy minimizations show that regular helices become less stable with increasing helix length. These findings indicate that the definition of 3(10)-helices in terms of average, uniform dihedral angles is not appropriate and that it is inherently unstable for a polypeptide to form an extended, regular 3(10)-helix. The 3(10)-helices observed in proteins are better referred to parahelices.     

流式细胞术在高等植物研究中的应用

流式细胞术(FCM)是根据所测定的各种细胞性质的不同组合,从细胞群体中把某个亚群分选出来,并对它的功能和形态学进行研究或进一步培养分析。流式细胞术具有快速、灵敏和同时进行多参数检测等优点,对其基本原理和在高等植物中的应用进行了介绍。     

Enterococcus faecium EK13--an enterocin a-producing strain with probiotic character and its effect in piglets

The experiment was conducted to determine the effects of the inoculation of the probiotic and enterocin A-producing strain Enterococcus faecium EK13 on selected parameters of metabolic profile, gut microflora, growth, and health in newborn piglets of Slovak White Improved. Piglets for study were divided into two groups: one group (EK13 group, n=8) received strain EK13 per os once daily for 7 days (2ml per piglet, 10(9)CFU/mL of saline buffer). The control group of piglets (n=7) was given placebo-saline buffer. The experiment lasted 14 days. After 7 days, strain EK13 reached 9.8 log(10) CFU/g in faeces of E. faecium EK13 treated piglets while counts of Escherichia coli were significantly lower (P<0.01) than in piglets of the control group. The concentrations of total serum protein, calcium, haemoglobin, haematocrit, red blood cell count and index of phagocytic activity of leukocytes were significantly higher after application of strain EK13. On the other hand, cholesterol was significantly lower in the EK13 group of animals. On day 14, piglets were killed and samples of intestinal contents were taken. Total counts of bacteria in the intestinal contents (jejunum, ileum, caecum, colon) were not significantly influenced. The pH value was significantly lower (P<0.05) only in duodenum of piglets receiving E. faecium EK13. There was a significant higher concentration of lactic acid (P<0.01) and propionic acid in the colon (P<0.001) of the EK13 group. Application of E. faecium EK13 did not influence the daily body weight gain significantly.     

Iterative kriging for removing spatial autocorrelation in analysis of forest genetic trials

Conventional analysis of spatially correlated data in inadequately blocked field genetic trials may give erroneous results that would seriously affect breeding decisions. Forest genetic trials are commonly very large and strongly heterogeneous, so adjustments for micro-environmental heterogeneity become indispensable. This study explores the use of geostatistics to account for the spatial autocorrelation in four Pinus pinaster Ait. progeny trials established on hilly and irregular terrains with a randomized complete block design and large blocks. Data of five different traits assessed at age 8 were adjusted using an iterative method based on semivariograms and kriging, and the effects on estimates of variance components, heritability, and family effects were evaluated in relation to conventional analysis. Almost all studied traits showed nonrandom spatial structures. Therefore, after the adjustments for spatial autocorrelation, the block and family × block variance components, which were extremely high in the conventional analysis, almost disappeared. The reduction of the interaction variance was recovered by the family variance component, resulting in higher heritability estimates. The removal of the spatial autocorrelation also affected the estimation of family effects, resulting in important changes in family ranks after the spatial adjustments. Comparison among families was also greatly improved due to higher accuracy of the family effect estimations. The analysis improvement was larger for growth traits, which showed the strongest spatial heterogeneity, but was also evident for other traits such as straightness or number of whorls. The present paper demonstrates how spatial autocorrelation can drastically affect the analysis of forest genetic trials with large blocks. The iterative kriging procedure presented in this paper is a promising tool to account for this spatial heterogeneity.     

核心种质数量性状代表性评价指标的研究

对植物核心种质数量性状遗传多样性代表性的评价指标进行了系统的研究．以夏播菜用大豆154个品种为材料,采用马氏距离计算品种间的距离,并用不加权类平均法(UPGMA)进行聚类,根据树型图,采用逐步聚类随机取样法,构建了37个品种组成的核心种质．以此为例,通过方差F测验、均值t测验、极差符合率、表型频率分布、遗传多样性指数、表型相关分析等多个指标分析,来评价核心种质数量性状遗传多样性的代表性,结果表明构建的核心种质具有代表性,表明核心种质评价需包含评价遗传变异和遗传结构的指标．     

Biochemical characterization of prephenate dehydrogenase from the hyperthermophilic bacterium Aquifex aeolicus

A monofunctional prephenate dehydrogenase (PD) from Aquifex aeolicus was expressed as a His-tagged protein in Escherichia coli and was purified by nickel affinity chromatography allowing the first biochemical and biophysical characterization of a thermostable PD. A. aeolicus PD is susceptible to proteolysis. In this report, the properties of the full-length PD are compared with one of these products, an N-terminally truncated protein variant (Delta19PD) also expressed recombinantly in E. coli. Both forms are dimeric and show maximum activity at 95 degrees C or higher. Delta19PD is more sensitive to temperature effects yielding a half-life of 55 min at 95 degrees C versus 2 h for PD, and values of kcat and Km for prephenate, which are twice those determined for PD at 80 degrees C. Low concentrations of guanidine-HCl activate enzyme activity, but at higher concentrations activity is lost concomitant with a multi-state pathway of denaturation that proceeds through unfolding of the dimer, oligomerization, then unfolding of monomers. Measurements of steady-state fluorescence intensity and its quenching by acrylamide in the presence of Gdn-HCl suggest that, of the two tryptophan residues per monomer, one is buried in a hydrophobic pocket and does not become solvent exposed until the protein unfolds, while the less buried tryptophan is at the active site. Tyrosine is a feedback inhibitor of PD activity over a wide temperature range and enhances the cooperativity between subunits in the binding of prephenate. Properties of this thermostable PD are compared and contrasted with those of E. coli chorismate mutase-prephenate dehydrogenase and other mesophilic homologs.     

Studies on the kinetic parameters for alcoholic fermentation by flocculent Saccharomyces cerevisiae strains and non-hydrogen sulfide-producing strains

Summary The growing demand for high quality products and the immense export potential that cacha?a represents, demonstrated especially during the past few years, have clearly indicated the necessity of establishing well-defined standards of quality, as well as effective means of controlling the process of production of this beverage. The objective of this study was the selection of S. cerevisiae yeast strains and the investigation of their influence on the kinetic parameters of fermentation. Ninety strains of S. cerevisiae isolated from distilleries of the state of Minas Gerais were evaluated with respect to the following parameters: flocculation capacity, production of H₂S and kinetic parameters of fermentation. The UFMGA 905 strain was used as a reference because it presented desirable characteristics for the production of cacha?a. Five strains presented high specific sedimentation velocities (SSV), indicating a high flocculation capacity, and two did not produce H₂S. The strains presented significant statistical differences for fermentation parameters: yield of ethanol; efficiency of substrate conversion to ethanol; ratio of substrate conversion to ethanol (Y _p/s), to cells (Y _x/s), to organic acids (Y _ac/s), and to glycerol (Y _g/s); and productivity. In general, the strains presented a good fermentative potential, with ethanol yields varying from 74.7 to 82.1% and an efficiency of 76.1–84.4%. All strains presented high productivities (4.6–6.6 g l⁻¹ h⁻¹), indicating that this parameter can be used in the selection of strains for the production of cacha?a.     

Revolutions in RNA secondary structure prediction

RNA structure formation is hierarchical and, therefore, secondary structure, the sum of canonical base-pairs, can generally be predicted without knowledge of the three-dimensional structure. Secondary structure prediction algorithms evolved from predicting a single, lowest free energy structure to their current state where statistics can be determined from the thermodynamic ensemble. This article reviews the free energy minimization technique and the salient revolutions in the dynamic programming algorithm methods for secondary structure prediction. Emphasis is placed on highlighting the recently developed method, which statistically samples structures from the complete Boltzmann ensemble.