Low Levels Of Discrimination Research Articles

Molecular Taxonomic Characterisation of Probiotic Strain Lactobacillus Sp. 50P1

ABSTRACTIn recent years interest in the probiotic lactobacilli has been stimulated by the use of these bacteria in products that are claimed to confer health benefits on the consumer. The probiotic effects are usually strain-specific, meaning that a correct identification is important to link the strain to the specific health effect. Taxonomical characterization of probiotic strains only in phenotypic and phisyological characteristics is often with low level of discrimination, probably due to their co-evolution in the same ecological niches. Thus, the nucleotide base techniques provide an accurate basis for phylogenetic analysis and identification. With this aim a probiotic strain Lactobacillus spp. 50P1 was studied.Trough the physiological characterization with API 50 CH the strain 50P1, was determinate as Lactobacillus helveticus, with low probability- 77,5%. Three PCR-based methods, species-specific PCR, of 16S rRNA gene sequencing, and restriction enzyme of 16S rDNA ARDRA analysis were used for reliable taxonomic characterization of probiotic strain Lactobacillus sp. 50P1. The sequence obtained from the strain was compared to those of Lactobacillus species held in GenBank and the belonging of the strain 50P1 to the species Lactobacillus helveticus was confirmed.

Neighborhood Racial Composition and Perceptions of Racial Discrimination: Evidence From the Black Women's Health Study

Little is known about the effects of social context or “place” factors (e.g., characteristics of local populations) on African Americans' perceptions and experiences of racism. Using data from 42,445 U.S. black women collected during the 1997 follow-up wave of the Black Women's Health Study, we investigated the association between neighborhood racial composition (“percent black” at the block-group level in 2000 Census data) and perceptions of racial discrimination. Perceived racial discrimination was measured using self-reports of the frequency of discrimination in “everyday” settings (e.g., being treated as if you are dishonest) and “lifetime” occurrences of discrimination on the job, in housing, and by the police. There was a linear inverse relationship between neighborhood percent black and perceived discrimination, i.e., higher percent black was associated with lower levels of discrimination. Our results support the conclusions that, relative to contexts in which blacks are a small minority, more evenly-mixed (i.e., integrated) contexts result in lower levels of discrimination (contact hypothesis), and mostly black contexts evidence the lowest levels of discrimination (ethnic density hypothesis).

Microbiological Evaluation of the New VITEK 2 Neisseria - Haemophilus Identification Card

VITEK 2 is an automated identification system for diverse bacterial and fungal species. A new card (the Neisseria-Haemophilus [NH] card) for the identification of Neisseria spp., Haemophilus spp., and other fastidious gram-negative or gram-variable microorganisms has been developed, but its performance in a routine clinical laboratory has not yet been evaluated. In this study, a total of 188 bacterial strains belonging to the genera Actinobacillus, Campylobacter, Capnocytophaga, Cardiobacterium, Eikenella, Gardnerella, Haemophilus, Kingella, Moraxella, and Neisseria were investigated. The NH card was able to identify 171 strains (91%) correctly without the need for extra tests; one strain (0.5%) was misidentified, and five strains (2.7%) could not be classified. Eleven strains (5.8%) were identified with a low level of discrimination, and simple additional tests were required to increase the correct-identification rate to 96.8%. The results were available within 6 h. Based on these results, the new VITEK 2 NH card appears to be a good method for the identification of diverse groups of fastidious organisms, which would otherwise require testing with multiple systems. However, more work is needed to evaluate the performance of VITEK 2 with regard to Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella bacteria because of the insufficient number of strains tested in this study. Moreover, further reduction of the detection time would be desirable.

Identifying Discriminating Locations for Cultivar Selection in Louisiana

Plant breeders generally conduct the selection phase of their program at few locations, mainly on the basis of geography and resource limitations. We conducted this study to identify test locations that optimize genotype selection on the basis of discriminating ability and representativeness. GGE Biplot Pattern Explorer was used to rank six test locations in Louisiana for cotton (Gossypium hirsutum L.) lint yield and fiber length using data from the 1993 to 2003 Louisiana Official Variety Trials (early and medium maturity). Biplots were generated and distances between the “ideal” and actual test locations were measured. Locations with shorter distances were closer to the ideal location and were considered more desirable test locations for the traits of interest. Each test location's distance was standardized by the mean distance of all locations for each biplot. For lint yield, on the basis of its close proximity to the ideal test location and the low standard deviation, the most desirable selection location was St. Joseph loam (Commerce silt loam; fine‐silty, mixed, nonacid, thermic, Aeric, Fluvaquent). Winnsboro nonirrigated and Bossier City were not good selection locations for lint yield. For fiber length, Winnsboro irrigated was ranked first and St. Joseph loam was ranked third. Winnsboro nonirrigated was ranked sixth. A composite distance, reflecting the distance between the actual and “ideal” location for lint yield weighted at 60% and fiber length weighted at 40%, was used to determine the desirability of test locations on the basis of simultaneous selection for lint yield and fiber length. St. Joseph loam ranked first, Winnsboro irrigated ranked second, and Winnsboro nonirrigated ranked sixth. St. Joseph loam or Winnsboro irrigated should be used for selecting cultivars for lint yield and fiber length. Winnsboro nonirrigated should not be used for selecting cultivars because of its low level of discrimination and unique behavior.

Prolactin releasing peptide has high affinity and efficacy at neuropeptide FF2 receptors.

Neuropeptide FF (NPFF) and prolactin-releasing peptide (PrRP) are two members of the RFamide peptide family. In this study we investigated whether these RFamide peptides, which have common structural features in their C-terminal RFamide motif and share several physiologically important functions, could exert their effects through the same set of receptors. The affinity and functional activity of several related RFamide peptides were determined at the human neuropeptide FF receptor subtype 2 (hNPFF2) and the human prolactin-releasing peptide (hPrRP) receptors. The full-length human prolactin releasing peptide 31 (hPrRP31) had significantly higher efficacy compared with NPFF and its stable analog, (1DMe)Y8Fa, at the hNPFF2 receptor. In contrast, NPFF and (1DMe)Y8Fa were not efficacious at the hPrRP receptor. Our study indicated a generally relatively low level of discrimination for RFamide peptides at the NPFF receptor, whereas the hPrRP receptor clearly preferred PrRP or very closely related peptides. The seemingly promiscuous binding of the RFamide peptides to the NPFF receptor was further confirmed by receptor autoradiography. PrRP may thus signal through the NPFF receptors in vivo.

Phosphoisoprenoid binding specificity of geranylgeranyltransferase type II.

Geranylgeranyltransferase type II (GGTase-II) modifies small monomeric GTPases of the Rab family by attaching geranylgeranyl moieties onto two cysteines of their C-terminus. We investigated to what extent GGTase-II discriminates between its native substrate geranylgeranyl pyrophosphate (GGpp) and other phosphoisoprenoids, including farnesyl pyrophosphate (Fpp). On the basis of a novel fluorescent assay, we demonstrated that GGpp binds to GGTase-II with an affinity of 8 +/- 4 nM, while Fpp is bound less strongly (K(d) = 60 +/- 8 nM). Analysis of the binding kinetics of four different phosphoisoprenoids indicated that in all cases association is rapid, with rate constants in the range of 0.15 nM(-1) s(-1). In contrast, the dissociation rates differed greatly, depending on the phosphoisoprenoid used, with weak binding substrates generally displaying an increased rate of dissociation. The affinity of GGpp and Fpp for GGTase-II was also determined in the presence of the Rab7-REP-1 complex. The affinity for GGpp was essentially unaffected by the presence of the complex; Fpp on the other hand bound less strongly to the GGTase-II under these conditions, resulting in a K(d) of 260 +/- 60 nM. In vitro prenylation experiments were used to establish that Fpp not only does bind to GGTase-II but also is transferred with an observed rate constant of 0.082 s(-1) which is very similar to that of GGpp. The implications of the low level of discrimination by GGTase-II for the in vivo specificity of the enzyme and the use of farnesyltransferase inhibitors in anti-cancer therapy are discussed.

Queen acceptance and nestmate recognition in monogyne and polygyne colonies of the antFormica truncorum

In ants permanent polygyny (the permanent presence of multiple reproducing queens) commonly arises secondarily through the adoption of daughter queens. Polygyny decreases the relatedness among nestmate workers and consequently the genetic benefits from helping close relatives. Hence, studies on nestmate recognition and queen adoption may shed light on how queen numbers are regulated as well as on causes of variation in queen number. In this study acceptance of nestmate and non-nestmate young queens in monogyne (single queen) and polygyne colonies of the antFormica truncorumwas compared. Queen number varies in this species: in some populations colonies have a single queen (monogyne populations), whereas in others all colonies contain several functional queens (polygyne populations). Young queens introduced into the experimental colonies varied with respect to female origin (nestmate versus non-nestmate), dispersal prospects as reflected by wing status (wingless versus winged) and mating status (mated versus virgin). Monogyne and polygyne colonies differed in one fundamental way in their responses to introduced females. Workers of monogyne colonies, but not those of polygyne colonies, discriminated between nestmate and non-nestmate females. In both monogyne and polygyne colonies mated females were destroyed to a higher extent than virgin ones, largely independently of wing status. None the less, mated females may have a reasonable chance of becoming adopted in their natal colony both in monogyne and polygyne colonies. If so, the single-queen status of monogyne colonies may be retained by a high rate of female dispersal in combination with few intra-nidal mating opportunities. Polygyne colonies are characterized by both a low degree of female rejection and low levels of discrimination between nestmates and non-nestmates. Nevertheless, previous genetic and behavioural data on female dispersal suggest that the majority of new queens adopted into polygyne colonies are their own daughters.

SOME DEMOGRAPHIC CORRELATES OF HIV/AIDS‐RELATED DISCRIMINATION

In late 1991, a survey was made of HIV/AIDS‐related discrimination in the Australian community. Structured telephone interviews were conducted with a random sample of 2,053 respondents. Twenty‐one questions provided an index of expressed discrimination. Social contact with HIV‐positive people was a significant predictor of low levels of discrimination. Other important predictors of (lower) levels of discrimination were: social contact with gay men, education, sex, age, sexual identity, and sexual experience. Social contact with gay men was the single best predictor of positive attitudes towards people with HIV/AIDS.

NOW THAT WE ARE HERE:

This article examines the sexist work experiences of a sample of women lawyers in a mediumsized midwestern city. Specifically, it focuses on reports of discrimination, gender disparagement, and sexual harassment as components of gendered systems that maintain and reinforce inequalities between men and women on the job. The relationships between these experiences, professional role orientation (feminist versus careerist) and structural work characteristics (types of workplace and deegree of tokenism) are explored. Respondents report lower levels of discrimination at the more visible and legally protected “front door” (in recruitment and hiring) than on the job (in salary, promotion, and job assignments). For the most part, private (versus public) sector employees and those in token positions report higher levels of sexist behavior. Contrary to expectations, those with careerist orientations (versus feminist orientations) report more sexual harassment. The interrelations and implications of these findings for women's careers in the law are discussed.

Analyse expérimentale de l'isolement reproductif entre deux espèces jumelles et sympatriques d'araignées : le Lycosa thorelli (Keyserling) et le Lycosa carbonelli Costa et Capocasale

Four experimental groups were used: (A) males Lycosa thorelli × female L. thorelli; (B) male Lycosa carbonelli × female L. carbonelli; (C) Male L. thorelli × female L. carbonelli; (D) male L. carbonelli × female L. thorelli. Males were placed in a field with conspecific sexual pheromone and confronted to anesthetized virgin females. Male L. thorelli showed a greater tenacity than male L. carbonelli in the maintenance of the copulatory position. The typical copulation pattern (intraspecific groups) became atypical in interspecific groups. Only one typical interspecific copulation was observed in group C. Male L. carbonelli showed a good specific discrimination when mounting the female, while male L. thorelli showed a low discrimination level. The maintenance of the copulatory position could be determined by a modal number of ejaculations in the case of male L. carbonelli and by a modal duration in the case of male L. thorelli. Atypical copulations might indicate a mechanical incompatibility between the genitalia of the two species. Typical copulations produced offspring, indicating the absence of postcopulatory isolation mechanisms.

Mechanism of DNA replication fidelity for three mutants of DNA polymerase I: Klenow fragment KF(exo+), KF(polA5), and KF(exo-)

Inhibition of the pre-steady-state burst of nucleotide incorporation by a single incorrect nucleotide (nucleotide discrimination) was measured with the Klenow fragment of DNA polymerase I [KF(exo+)]. For the eight mispairs studied on three DNA sequences, only low levels of discrimination ranging from none to 23-fold were found. The kinetics of dNTP incorporation into the 9/20-mer at low nucleotide concentrations was also determined. A limit of greater than or equal to 250 s-1 was placed on the nucleotide off-rate from the KF(exo+)-9/20-dTTP complex in accord with nucleotide binding being at equilibrium in the overall kinetic sequence. The influence of the relatively short length of the 9/20-mer on the mechanism of DNA replication fidelity was determined by remeasuring important kinetic parameters on a 30/M13-mer with high homology to the 9/20-mer. Pre-steady-state data on the nucleotide turnover rates, the dATP(alpha S) elemental effect, and the burst of dAMP misincorporation into the 30/M13-mer demonstrated that the kinetics were not affected by the length of the DNA primer/template. The effects on fidelity of two site-specific mutations, KF(polA5) and KF(exo-), were also examined. KF(polA5) showed an increased rate of DNA dissociation and a decreased rate of polymerization resulting in less processive DNA synthesis. Nevertheless, with at least one misincorporation event, that of dAMP into the 9/20-mer, KF(polA5) displays an increased replication fidelity.(ABSTRACT TRUNCATED AT 250 WORDS)

Permeation of divalent cations through alpha-latrotoxin channels in lipid bilayers: steady-state current-voltage relationships.

alpha-Latrotoxin, a polypeptide neurotoxin known to cause massive release of transmitter from vertebrate nerve terminals, is thought to act by forming cation-selective channels in plasma membranes. This paper describes the steady-state current carried by Ca2+, Sr2+ and Ba2+ through pores of alpha-LaTx molecules incorporated in artificial bilayer membranes made of neutral lipids. Even when the solutions separated by the membrane are identical, the I-V relations rectify strongly, the current being higher when the side to which the toxin is added is positive. The polarity of the rectification is consistent with the hypothesis that the mechanism of action of the toxin is, at least in part, that of promoting inwardly directed flow of cations, and thus, accumulation of Ca2+ and other ions in the intracellular spaces. The dependence of the I-V characteristics on voltage and Ca2+ concentration is well described by a one-site, one-ion model for a channel. Three parameters of the model are deduced: the binding constant of the site for Ca2+, K = 1.5 M-1 (or K = 7 M-1 when activities are used instead of concentrations); the "electrical" distance of the site from the toxin-containing solution, alpha = 0.3; the free energy difference between the two barrier peaks, delta F = 0.26 kT. The values of the parameters deduced by studying the channel in the presence of Ca2+ give theoretical curves that also fit the data with Sr2+ and Ba2+, indicating a low level of discrimination among these three cations.

Dichotic sequence discrimination: The effect of continued practice

Dichotic sequence discrimination was studied by means of a three-alternative forced-choice method. Two of the alternatives (‘same’) consisted of a single pair of dichotic clicks with the stimulus at one ear preceding the stimulus at the other ear by a given temporal separation (e.g., R-Δt-L). One of the alternatives consisted of a single pair of clicks with the opposite sequence (e.g., L-Δt-R). The subjects' task was to discriminate between the ‘different’ and the ‘same’ dichotic pairs. The results indicate that discrimination is a nonmonotonic function of Δt, i.e., V- or U-shaped, with high levels at both short and long temporal separations (Δt=2 and 4 ms and Δt=64 and 96 ms) and with lower levels of discrimination for intermediate Δts. A second experiment was performed to study the effect of continued practice by subjects trained in dichotic sequence discrimination for Δts 4 and 64 ms (high discrimination levels) and for Δt=16 ms (low discrimination level). There was no systematic trend towards improvement over 8 blocks of 50 trials for each Δt. Discrimination levels of these Δts did not differ between Experiments 1 and 2.

Electron detection efficiency of a Nal(Tl) scintillator for electrons and for gamma rays above a few keV

A technique is developed for the analysis of photoelectron pulse amplitude distributions from gamma rays or electrons of selected energy observed with a GaP first dynode photomultiplier, taking into account the time-spread of photon emission from the Nal(Tl) scintillator. The observed amplitude distribution is decomposed into a unique sum of experimentally based, constructed amplitude distributions (with relative intensities f n ), one for each number n of photoelectrons emitted in each detected event. It is experimentally verified that, for unique energy deposition in the scintillator, the pulse amplitude distribution gives rise to a number distribution f n , which is Poisson P m ( n), and also that the loss of detected events above a very low discrimination level is accurately given by the Poisson prediction for events which fail to release even one photoelectron, i.e., P m (0). For a spectrum of energies actually deposited in the crystal due to various degrees of back-scattering of an impinging electron with given energy, the derived f n distribution below n = 10 is analyzed into a quasi continuum of weighted Poisson distributions. The efficiency loss for any given discrimination level can be obtained from this continuous function. The method is shown to work down to an intrinsic detection efficiency of 10% for very low energy gamma rays and down to at least 5 keV for electrons. Reasons for disagreement between observation and expectation in the range 2.6-5 keV for electrons are discussed.

Pulse Shape Discrimination System for 6LiF(ZnS) Scintillation Counters

A pulse shape discrimination system for 6LiF(ZnS) scintillators is described and its electronic layout discussed. Test results under typical operation conditions at the location of a neutron scattering experiment in a light water research reactor are given. They show that the system is able to suppress virtually all spurious (γ and tube noise) pulses down to a rather low discrimination level. By taking a low discrimination level it is possible to exploit the potentially high efficiency of the scintillator to a much larger extent. In our particular case the over-all counting efficiency could be doubled.