Relationships among the muscle strength properties as assessed through various tests and variables

We tested the hypotheses that the individual strength properties depend on the applied test and the variable extracted, rather than on the muscle group tested. Flexor and extensor muscles acting in the knee and elbow joint were tested in 58 participants. The standard strength test (SST; based on sustained maximum contraction) and alternating consecutive maximum contractions (ACMCs; alternating contractions of antagonistic muscles) performed under static conditions were separately applied to provide the maximum force (F) and the rate of force development (RFD) of each tested muscle. The principal component analysis applied on all 16 variables revealed three factors that explained 85.5% of the total variance. Contrary to our hypotheses, the individual factors were loaded with the variables recorded from individual muscles, rather than with either the particular variables or tests. The present findings suggest that recording both F and RFD in routine strength testing procedures could be redundant since they may assess the same strength property of the tested muscle. In addition, ACMC may be a feasible alternative to SST since it could assess the same strength properties from two antagonist muscles through a single trial, while being based on relatively low and transient forces.     

Neural networks distinguish between taste qualities based on receptor cell population responses.

Response features of taste receptor cell action potentials were examined using an artificial neural network to determine whether they contain information about taste quality. Using the loose patch technique to record from hamster taste buds in vivo we recorded population responses of single fungiform papillae to NaCl (100 mM), sucrose (200 mM) and the synthetic sweetener NC-00274-01 (NC-01) (200 microM). Features of each response describing both burst and inter-burst characteristics were then presented to an artificial neural network for pairwise classification of taste stimuli. Responses to NaCl could be distinguished from those to both NC-01 and sucrose with accuracies of up to 86%. In contrast, pairwise comparisons between sucrose and NC-01 were not successful, scoring at chance (50%). Also, comparisons between two different concentrations of NaCl, 0.01 and 0.005 M, scored at chance. Pairwise comparisons using only those features that relate to the inter-burst behavior of the response (i.e. bursting rate) did not hinder the performance of the neural network as both sweeteners versus NaCl received scores of 75--85%. Comparisons using features corresponding to each individual burst scored poorly, receiving scores only slightly above chance. We then compared the sweeteners with varying concentrations of NaCl (0.1, 0.01, 0.005 and 0.001 M) using only those features corresponding to bursting rate within a 1 s time window. The neural network was capable of distinguishing between NaCl and NC-01 at all concentrations tested; while comparisons between NaCl and sucrose received high scores at all concentrations except 0.001 M. These results show that two different taste qualities can be distinguished from each other based solely on the bursting rates of action potentials in single taste buds and that this distinction is independent of stimulation intensity down to 0.001 M NaCl. These data suggest that action potentials in taste receptor cells may play a role in taste quality coding.     

Relationships between taste reactivity and intake in the neurologically intact rat

To investigate the differences between short-term intake testsand taste reactivity responses to tastes, rats received 1-minintraoral infusions of a variety of tastants delivered at therate of 1 ml/min. Oral responses were videotaped and analysedin terms of the sequence and number of ingestive and aversivetaste reactivity response components evoked. Intake was alsomeasured. The number of rats displaying ingestive taste reactivitycomponents and the mean number of ingestive components displayedper rat elicited by sucrose and NaCl increased with increasingconcentration. Intake was high across all concentrations. HClinfusions elicited alternation between ingestive and aversiveresponse components. The number of rats displaying aversivetaste reactivity response components and the mean number ofaversive response components displayed per rat, elicited byQHCl, increased with increasing concentration, while both intakeand the median latency to reject QHCl decreased (ExperimentI). To determine whether other tastes judged bitter by humanswould elicit a quinine-like taste reactivity response in therat, sucrose octa-acetate (SOA), quinine sulfate (QS) and caffeine(CAF) stimuli were examined. Both QS and CAF infusions elicitedan increased number of aversive response components with increasingconcentration, and intake decreased. SOA infusions elicitedalternation between ingestive and aversive response componentsfollowed by a display of solely aversive components, and bothintake and median latency to reject the infusions decreasedsignificantly with increased concentration (Experiment II).Experiment I demonstrated that hypertonic NaCl infusions elicitingestive response components, while short-term intake testsshow that hypertonic NaCl is rejected and is thus inferred tobe aversive. Rats received prolonged infusions of hypertonicNaCl solutions at the rate of 1 ml/min until fluid was seenon the surface of the chamber, indicating rejection. Prolongedinfusions of hypertonic NaCl solutions elicited an initial displayof solely ingestive response components followed by an abruptshift to solely aversive response components and active fluidrejection. Higher concentrations elicited this shift soonerthan lower ones (Experiment III). The results suggest that patternsof taste reactivity response components are good predictorsof intake duration.     

Differential context effects in taste perception

A series of three experiments explored differential contexteffects in judgements of taste intensity. For example, a givenconcentration of NaCl was judged stronger than a given concentrationof sucrose in one contextual condition (where the stimulus setcomprised low concentrations of NaCl and high ones of sucrose),but was judged weaker in another condition (where the concentrationsreversed). Overall, differential context effects were largerwhen subjects judged NaCl and sucrose than when they judgedNaCl and NaCl sucrose mixtures, an outcome predicted by thehypothesis that the magnitude of differential context effectsdepends on the degree of qualitative similarity between thesubsets of stimuli. This pattern of results mimics those previouslyobtained for judgements of loudness of tones at different soundfrequencies, and thereby suggests that a common mechanism mayunderlie contextual interactions in different modalities; moreover,this mechanism may bear implications for current theories ofthe coding of taste quality and intensify.     

Relationships among <Emphasis Type="Italic">Leymus</Emphasis> species assessed by RAPD markers

The DNA genetic diversity of 40 accessions of genus Leymus was analyzed by random amplified polymorphic DNA (RAPD) markers. A total of 352 products were amplified by 34 10-mer arbitrary primers, among which 337 products (95.74 %) were found to be polymorphic. 5–14 polymorphic bands were amplified by each polymorphic primer, with an average of 9.91 bands. The data of 352 RAPD bands were used to generate Jaccard’s similarity coefficients and to construct a dendrogram by means of UPGMA. Great genetic diversity in genus Leymus was observed, the genetic diversity among the different species more abundant than that of the different accessions, and the different accessions in a species or the species from the same areas were clustered together.     

Biological effects of cigarette smoking assessed with the NBT test

The NBT reduction spontaneous and stimulated test was carried out on 90 men; 30 of which had never smoked cigarettes, 28 subjects have smoked for up to 10 years and 32 subjects--since over 10 years. The investigations demonstrated show that in subjects smoking cigarettes for up to 10 years the spontaneous and stimulated ability of the neutrophils to reduce NBT was increased whereas in the subjects smoking cigarettes since over 10 years impairment of the stimulated NBT reduction was demonstrated. We've come to a conclusion that an exposure to tobacco smoke may activate oxidation-reduction processes of the neutrophils in the initial stage and impair them in longer stage of smoking.     

Relationships between migration rates and landscape resistance assessed using individual-based simulations

Linking landscape effects on gene flow to processes such as dispersal and mating is essential to provide a conceptual foundation for landscape genetics. It is particularly important to determine how classical population genetic models relate to recent individual-based landscape genetic models when assessing individual movement and its influence on population genetic structure. We used classical Wright-Fisher models and spatially explicit, individual-based, landscape genetic models to simulate gene flow via dispersal and mating in a series of landscapes representing two patches of habitat separated by a barrier. We developed a mathematical formula that predicts the relationship between barrier strength (i.e., permeability) and the migration rate (m) across the barrier, thereby linking spatially explicit landscape genetics to classical population genetics theory. We then assessed the reliability of the function by obtaining population genetics parameters (m, F(ST) ) using simulations for both spatially explicit and Wright-Fisher simulation models for a range of gene flow rates. Next, we show that relaxing some of the assumptions of the Wright-Fisher model can substantially change population substructure (i.e., F(ST) ). For example, isolation by distance among individuals on each side of a barrier maintains an F(ST) of ～0.20 regardless of migration rate across the barrier, whereas panmixia on each side of the barrier results in an F(ST) that changes with m as predicted by classical population genetics theory. We suggest that individual-based, spatially explicit modelling provides a general framework to investigate how interactions between movement and landscape resistance drive population genetic patterns and connectivity across complex landscapes.     

Serological Relationships among Some Pichia Species

Antigenic analyses of five species of the genus Pichia were carried out for taxonomic study by the slide agglutination method using monospecific and absorbed antisera and the agglutinin absorption technique. Comparative studies were also performed with a few strains of each of the same species and their classifications are discussed with respect to the antigenic structures and the patterns of proton magnetic resonance (PMR) spectra of their cell wall polysaccharides. Pichia delftensis and Pichia zaruensis possessed thermostable antigens 1, 2, 5 and 11, and the former had also thermolabile antigen m. Both species were closely related to Candida krusei. Pichia toletana possessed thermostable antigens 1, 2, 5, 11, 17 and 49. Pichia bovis contained thermostable antigens 1, 2, 14, 15, 16, 20 and 21, and it was related to most species of the genus Hansenula, although assimilation of potassium nitrate was negative. Finally, Pichia etchellsii possessed thermostable antigens 1, 2, 3, 4, 9 and 14, and was closely related to Pichia vini. Patterns of PMR spectra of mannans of these species also supported their serological relationships. Therefore, P. delftensis, P. zaruensis and P. etchellsii are considered to be the synonyms of Pichia fluxuum, Pichia dispora and P. vini respectively, although P. toletana and P. bovis are independent species.     

Relationships among biomarkers of one-carbon metabolism

One-carbon metabolism is a network of metabolic pathways, disruption of which has been associated with cancer and other pathological conditions. Biomarkers of these pathways include homocysteine (HCY), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH). A better understanding of the relationships between these biomarkers is needed for their utilization in research. This study investigated the relationships between fasting concentrations of plasma HCY, SAM, SAH and the ratio of SAM:SAH, and serum folate, vitamin B(12) and creatinine in a healthy adult population. A cross-sectional study recruited 678 volunteers; only subjects with complete data (n = 581) were included in this analysis. Correlations were used to examine bivariate relationships among the biomarkers and multivariate linear regression determined independent relationships with HCY, SAM and SAH treated as dependent variables in separate models. Multivariate logistic regression examined determinants of a low SAM:SAH ratio (defined as having a SAM:SAH ratio in the bottom quartile and SAH value in the top quartile). HCY correlated inversely with folate and vitamin B(12) and weakly correlated with SAH and creatinine. Both SAM and SAH correlated with creatinine but were independent of serum folate and vitamin B(12). In multivariate analyses, folate, vitamin B(12), creatinine, sex and age were associated with HCY; age and creatinine were determinants of SAM, and sex and creatinine determinants of SAH. Finally, male sex and increasing creatinine levels were associated with having a low SAM:SAH ratio. Findings suggest that HCY, SAM and SAH are relatively independent parameters and reflect distinct aspects of one-carbon metabolism.     

Quantifying Antigenic Relationships among the Lyssaviruses

All lyssaviruses cause fatal encephalitis in mammals. There is sufficient antigenic variation within the genus to cause variable vaccine efficacy, but this variation is difficult to characterize quantitatively: sequence analysis cannot yet provide detailed antigenic information, and antigenic neutralization data have been refractory to high-resolution robust interpretation. Here, we address these issues by using state-of-the-art antigenic analyses to generate a high-resolution antigenic map of a global panel of 25 lyssaviruses. We compared the calculated antigenic distances with viral glycoprotein ectodomain sequence data. Although 67% of antigenic variation was predictable from the glycoprotein amino acid sequence, there are in some cases substantial differences between genetic and antigenic distances, thus highlighting the risk of inferring antigenic relationships solely from sequence data at this time. These differences included epidemiologically important antigenic differences between vaccine strains and wild-type rabies viruses. Further, we quantitatively assessed the antigenic relationships measured by using rabbit, mouse, and human sera, validating the use of nonhuman experimental animals as a model for determining antigenic variation in humans. The use of passive immune globulin is a crucial component of rabies postexposure prophylaxis, and here we also show that it is possible to predict the reactivity of immune globulin against divergent lyssaviruses.Rabies remains a globally important zoonosis, despite being one of the oldest recognized infectious diseases (27, 55). The majority of rabies in terrestrial animals and humans is caused by classical rabies virus (RABV), a lyssavirus in the family Rhabdoviridae. Since the 1950s, many related lyssaviruses which are capable of causing clinical rabies have been identified. The majority of those viruses have been isolated from bats (Chiroptera), including four divergent viruses, which were isolated in separate geographic locations throughout Eurasia in the past 18 years (2, 29, 31). The Chiroptera, therefore, represent a global reservoir for lyssaviruses, creating the potential for “spillover” infection to terrestrial mammals, including humans. Occasionally transmission between members of a new host species will occur, with potential for a subsequent adaptation in that species (35). Phylogenetic evidence suggests that one or more host-switching events from bats into terrestrial mammals were originally responsible for the ongoing global epidemic of terrestrial RABV (6).Pre- or postexposure prophylaxis, using vaccination and passive immune globulin administration according to World Health Organization (WHO) guidelines, is currently the only effective way to prevent rabies after infection with a lyssavirus (1). The efficacy of both active and passive immunization is likely to be affected by antigenic differences between viruses. The lyssavirus trimeric glycoprotein is the primary surface antigen, the major target for neutralizing antibodies (8), and is involved in cell binding and entry (34, 36, 53). Antigenic sites on the glycoprotein have been described using monoclonal antibody escape mutants (8, 16, 47, 51). These studies have elucidated two major sites (sites II and III) and multiple minor sites. Although estimates of antigenic differences can be made using information regarding these known antigenic sites, protein structure, and amino acid properties, predictions of the relative importance of those sites and specific mutations within those sites cannot be quantitatively tested without a method to reliably measure antigenic effect.The use of serological cross neutralization data to measure antigenic difference is limited by the reliability of the serological test and, more importantly, by paradoxes, or irregularities in the data. These irregularities include higher heterologous than homologous titers and individual variations between sera raised against the same antigen (22, 52). Hence, serological data are considered to have low resolution, and they are often used only qualitatively. Despite these difficulties, studies have attempted to further quantify antigenic differences among lyssaviruses. Badrane et al. (5) showed a linear correlation between the glycoprotein amino acid identity and four cross neutralization titers. Other studies have demonstrated variable serological cross-reactivity between European bat lyssaviruses (EBLV) and RABVs (10, 11) and suggested that antigenic relationships between EBLV-1 and EBLV-2 may not be fully reflected in the genetic relationships (41). Recent investigations into the efficacy of biologics against the Eurasian lyssaviruses showed an array of relatedness between lyssavirus species, with, for example, a murine anti-Aravan virus (anti-ARAV) serum neutralizing Khujand virus (KHUV) and ARAV equally but an anti-KHUV serum being less effective at neutralizing ARAV than KHUV (22). Until recently, however, there were no established tools for the quantitative analysis of antigenic data.Here we resolve the issue of quantitative interpretation of antigenic data using antigenic cartography. Antigenic cartography is a theory and associated computational method that resolves the paradoxes in the interpretation of antigenic data and makes possible high-resolution quantitative analyses and visualizations of binding assay data (15, 20, 25, 44, 49, 52).Integrating antigenic data with direct sequencing data, here we quantify the antigenic and genetic variation among a global panel of lyssaviruses, including representatives from all lyssavirus species. Furthermore, we address two key issues in the development of antilyssavirus biologics: the appropriateness of animal models and the development of efficacious alternatives to human rabies immune globulins (HRIGs).     

Relationships ofLomatium among other genera ofApiaceae

Lomatium is the largest North American genus ofApiaceae (=Umbelliferae). Relations amongLomatium and other genera have not been well understood. TheApiaceae-Araliaceae lineage and genera of North AmericanApiaceae were analyzed phenetically and cladistically in turn, and seven phenetic alliances of genera are identified. Data on frequencies of character-state combinations were assembled and usingSporne's notions of maximal and minimal co-variation of states, two character-states were identified that are derived among Umbellifer genera. Using cladistic analysis of the alliance consisting ofLomatium and six other genera we identified three sister groups toLomatium:Polytaenia alone;Polytaenia withPseudocymopterus, and a group of four genera. Not all genera in the group of seven withLomatium are supported by autapomorphies impeding phylogenetic reconstructions. Both phenetics and cladistics have helped to suggest and evaluate relationships; to call attention to groups requiring further study, and in particular to identify derived character-states.     

Fermented products with probiotic qualities

For several centuries, fermented products derived from plant or animal materials have been an acceptable and essential part of the diet in most parts of the world. Health benefits have also often been associated with them. Probiotics can be defined as fermented food containing specific live microorganisms or a live microbial food or feed supplement, which beneficially effects the human or the host animal by improving its intestinal microbial balance. Nearly all probiotics currently on the market contain Lactobacilli, Streptococci, Enterococci or Bifidobacteria. In contrast to Japan, where freeze-dried microorganisms are consumed by a substantial part of the human population, in Europe, probiotic action towards humans are only claimed for certain fermented dairy products (e.g. yoghurts). Those species that have been extensively studied so far, with several experimental trials on man, are the two yoghurt bacteria Streptocaccus thermophilus and Lactobacillus bulgaricus, L. casei and Bifidobacteria. L. acidophilus has also received important scientific interest, however, only a few human studies have been carried out. From the technological point of view a good probiotic should be stable and viable for long periods under storage, should be able to survive the low pH levels of the stomach, be able to colonise the epithelium of the gastro-intestinal tract of the host, should not be pathogenic and, last but not least, must be capable of exerting a growth promoting effect or a resistance to infectious diseases. The beneficial effects of probiotics are mainly contributed to a direct antagonistic effect against specific groups of microorganisms (Enteropathogenes), by an effect on the metabolism in the gut or by a stimulation of systemic or mucosal immunity. We will present major proven health benefits of milks fermented with those bacterial species and discuss, where possible, the impact of the specific selection and utilisation of particular strains.     

Bivalent effects of wheel running on taste conditioning

We replicated the finding of bivalent conditioning of tastes by wheel running by Hughes and Boakes (2008), but without pre-exposure to the wheel. Rats received six days of conditioning with a flavoured solution presented for 10 min before a 40-min placement in a running wheel and another flavoured solution presented for 10 min after. A highly palatable liquid meal replacement was used as a vehicle for the flavours to encourage consumption, allowing us to equate before and after presentation intervals. Relative to a third flavour, we found that the taste preceding wheel running was consumed less, and the taste that followed wheel running was consumed more. Novel wheel running can therefore condition both taste avoidance and taste preference.     

Polynucleotide Sequence Relationships among Members of Enterobacteriaceae

Polynucleotide relationships were examined among many representatives of the Enterobacteriaceae by means of agar, membrane filter, and hydroxyapatite procedures. The amount of deoxyribonucleic acid (DNA) that reassociated was dependent, especially in interspecific reactions, on the annealing temperature. In only three cases: Escherichia coli-Shigella flexneri, Salmonella typhimurium-S. typhi, and Proteus mirabilis-P. vulgaris, was relative interspecific duplex formation 80% or higher. In most cases interspecies DNA duplex formation was 40% or less of that obtained from intraspecies DNA reassociation reactions. The stability of E. coli-S. flexneri DNA duplexes formed at either 60 or 75 C was virtually identical to that of homologous E. coli DNA duplexes, and the degree of interspecies duplex formation was minimally affected by the temperature increase (86% at 60 C; 77% at 75 C). The thermal stability of DNA duplexes formed at 60 C between DNA from E. coli and DNA from strains of Aerobacter aerogenes, S. typhimurium, S. typhi, and P. mirabilis was about 12 to 14 C below that of reassociated E. coli DNA. At 75 C, the formation of the interspecific DNA duplexes was markedly decreased, but the stability of the DNA able to reassociate at this temperature approximated that of reassociated E. coli DNA. The degree of reassociation and the thermal stability of E. coli-S. flexneri DNA duplexes suggests relatively little evolutionary divergence in these organisms. The other enterobacteria tested, however, have diverged to a point where less than one-half of their DNA can reanneal with E. coli DNA at 60 C and less than 10% reacts at 75 C. The degree of divergence between various enterobacteria does not appear to be uniform along the DNA molecule. Ribosomal ribonucleic acid (RNA)-specific sequences are conserved among most enterobacteria. An examination of messenger RNA relatively specific for the lactose operon suggests that specific chromosomal genes may diverge more or less than the genome as a whole.     

应用RAMP分子标记探讨拟鹅观草属的种间关系

采用RAMP (random amplified microsatellite polymorphism) 标记技术, 分析了拟鹅观草属9种1亚种和鹅观草属6 种植物之间的遗传变异和亲缘关系。33 个引物组合产生的310 条DNA扩增片段中, 286条(92 25%) 具有多态性, 每个引物组合产生5~13条多态性带, 平均为8 67条。利用310个RAMP标记, 在NTSYS pc软件中, 计算Jaccard遗传相似系数, 建立UPGMA聚类图。结果表明: (1) 物种间遗传差异明显, 具有丰富的遗传多样性; (2) 阿拉善鹅观草和大丛鹅观草与拟鹅观草属的物种聚类在一起, 表明它们与拟鹅观草属的亲缘关系较近, 而与本试验所分析的另外4个鹅观草属物种的亲缘关系较远; (3) RAMP分子标记可以将拟鹅观草属的物种分开, 而且形态相似、地理分布相同或相近的物种聚类在一起;(4) RAMP结果与形态学和细胞学的分析结果一致, 表明RAMP标记是评价拟鹅观草属种间关系十分有效的方法。     

Functional status of the regenerated chorda tympani nerve as assessed in a salt taste discrimination task

We tested whether the recovered ability of rats to discriminate NaCl from KCl after chorda tympani nerve transection (CTX) is causally linked to nerve regeneration or some other compensatory process. Rats were presurgically trained in an operant NaCl vs. KCl discrimination task. Rats with regenerated nerves, histologically confirmed by anterior tongue taste pore counts and tested 62 days after CTX (CTX-62R; n = 5), performed as well as those tested 62 days after sham surgery (Sham-62; n = 5), but both of these groups initially performed slightly worse than animals tested 7 days after sham surgery (Sham-7; n = 4). Performance of rats tested either 7 (CTX-7P; n = 5) or 62 (CTX-62P; n = 4) days after CTX in which nerve regeneration was prevented was severely disrupted. Adulteration of the stimuli with amiloride, an epithelial sodium channel blocker, impaired discrimination performance in a similar dose-dependent manner in the Sham-7 (n = 2), Sham-62 (n = 5), and CTX-62R (n = 5) groups, suggesting that the functional status of the amiloride-sensitive transduction pathway returns to normal in rats with regenerated chorda tympani nerves. Performance of CTX rats without regenerated nerves (CTX-7P, n = 2; CTX-62P, n = 4) was further degraded by amiloride treatment, suggesting that taste receptors innervated by other nerves are sensitive to amiloride. In conclusion, nerve regeneration is an essential component underlying full recovery of salt discrimination function after CTX.     

Relationships among frozen-thawed sperm characteristics assessed via the routine semen analysis, sperm functional tests and fertility of bulls in an artificial insemination program

Frozen semen specimens from 22 Holstein bulls representing a wide range of field fertility levels or nonreturn rates (NRR) were used in this study. Semen specimens were thawed at 37 degrees C for a minimum of 30 sec, followed by assessment via a routine semen analysis (RSA) and other sperm functional tests. The RSA was performed by assessing sperm count, motility and morphological characteristics. Other sperm functional tests were performed by assessing the acrosomal membrane integrity, sperm penetration into the cervical mucus and the sperm membrane functional integrity. Following assessment of sperm characteristics, the fertility data of the various bulls were compared to the RSA and the functional tests results. Bulls of high and low fertility were similar in terms of sperm count and progressive motility (P > 0.05). Other characteristics measured by the RSA and functional tests were significantly higher in high fertility bulls (P < 0.05). Correlation coefficients among the various sperm characteristics and fertility of bulls were highly significant (P < 0.01). The highest correlation coefficients between sperm characteristics and fertility were obtained for motility (r = 0.53; P < 0.01), normal morphology (r = 0.59; P < 0.01) and swollen spermatozoa (r = 0.57; P < 0.01). Analysis of specific sperm swelling patterns showed that those patterns considered to reflect maximal sperm swelling were indicative of high fertility.