Differential effects of sodium ions on motility in the homoacetogenic bacteria Acetobacterium woodii and Sporomusa sphaeroides

1995 ◽  
Vol 164 (5) ◽  
pp. 363-369 ◽  
Author(s):  
V. Müller ◽  
Susanne Bowien
2003 ◽  
Vol 69 (2) ◽  
pp. 779-786 ◽  
Author(s):  
Hamadi I. Boga ◽  
Andreas Brune

ABSTRACT Although homoacetogenic bacteria are generally considered to be obligate anaerobes, they colonize the intestinal tracts of termites and other environments that are not entirely anoxic in space or time. In this study, we investigated how homoacetogenic bacteria isolated from the hindguts of various termites respond to the presence of molecular oxygen. All strains investigated formed growth bands in oxygen gradient agar tubes under a headspace of H2-CO2. The position of the bands coincided with the oxic-anoxic interface and depended on the O2 partial pressure in the headspace; the position of the bands relative to the meniscus remained stable for more than 1 month. Experiments with dense cell suspensions, performed with Clark-type O2 and H2 electrodes, revealed a large capacity for H2-dependent oxygen reduction in Sporomusa termitida and Sporomusa sp. strain TmAO3 (149 and 826 nmol min−1 mg of protein−1, respectively). Both strains also reduced O2 with endogenous reductants, albeit at lower rates. Only in Acetonema longum did the basal rates exceed the H2-dependent rates considerably (181 versus 28 nmol min−1 mg of protein)−1). Addition of organic substrates did not stimulate O2 consumption in any of the strains. Nevertheless, reductive acetogenesis by cell suspensions of strain TmAO3 was inhibited even at the lowest O2 fluxes, and growth in nonreduced medium occurred only after the bacteria had rendered the medium anoxic. Similar results were obtained with Acetobacterium woodii, suggesting that the results are not unique to the strains isolated from termites. We concluded that because of their tolerance to temporary exposure to O2 at low partial pressures (up to 1.5 kPa in the case of strain TmAO3) and because of their large capacity for O2 reduction, homoacetogens can reestablish conditions favorable for growth by actively removing oxygen from their environment.


2001 ◽  
Vol 120 (5) ◽  
pp. A215-A215
Author(s):  
P BARDHAN ◽  
S HUQ ◽  
S SARKER ◽  
D MAHALANABIS ◽  
K GYR

2001 ◽  
Vol 120 (5) ◽  
pp. A173-A174
Author(s):  
F BASCHIERA ◽  
C BLANDIZZI ◽  
M FOMAI ◽  
M TACCA

2016 ◽  
Vol 37 (4) ◽  
pp. 239-249
Author(s):  
Xuezhu Ren ◽  
Tengfei Wang ◽  
Karl Schweizer ◽  
Jing Guo

Abstract. Although attention control accounts for a unique portion of the variance in working memory capacity (WMC), the way in which attention control contributes to WMC has not been thoroughly specified. The current work focused on fractionating attention control into distinctly different executive processes and examined to what extent key processes of attention control including updating, shifting, and prepotent response inhibition were related to WMC and whether these relations were different. A number of 216 university students completed experimental tasks of attention control and two measures of WMC. Latent variable analyses were employed for separating and modeling each process and their effects on WMC. The results showed that both the accuracy of updating and shifting were substantially related to WMC while the link from the accuracy of inhibition to WMC was insignificant; on the other hand, only the speed of shifting had a moderate effect on WMC while neither the speed of updating nor the speed of inhibition showed significant effect on WMC. The results suggest that these key processes of attention control exhibit differential effects on individual differences in WMC. The approach that combined experimental manipulations and statistical modeling constitutes a promising way of investigating cognitive processes.


Author(s):  
Lisa Irmen ◽  
Julia Kurovskaja

Grammatical gender has been shown to provide natural gender information about human referents. However, due to formal and conceptual differences between masculine and feminine forms, it remains an open question whether these gender categories influence the processing of person information to the same degree. Experiment 1 compared the semantic content of masculine and feminine grammatical gender by combining masculine and feminine role names with either gender congruent or incongruent referents (e.g., Dieser Lehrer [masc.]/Diese Lehrerin [fem.] ist mein Mann/meine Frau; This teacher is my husband/my wife). Participants rated sentences in terms of correctness and customariness. In Experiment 2, in addition to ratings reading times were recorded to assess processing more directly. Both experiments were run in German. Sentences with grammatically feminine role names and gender incongruent referents were rated as less correct and less customary than those with masculine forms and incongruent referents. Combining a masculine role name with an incongruent referent slowed down reading to a greater extent than combining a feminine role name with an incongruent referent. Results thus specify the differential effects of masculine and feminine grammatical gender in denoting human referents.


2020 ◽  
Vol 51 (3) ◽  
pp. 183-198
Author(s):  
Wiktor Soral ◽  
Mirosław Kofta

Abstract. The importance of various trait dimensions explaining positive global self-esteem has been the subject of numerous studies. While some have provided support for the importance of agency, others have highlighted the importance of communion. This discrepancy can be explained, if one takes into account that people define and value their self both in individual and in collective terms. Two studies ( N = 367 and N = 263) examined the extent to which competence (an aspect of agency), morality, and sociability (the aspects of communion) promote high self-esteem at the individual and the collective level. In both studies, competence was the strongest predictor of self-esteem at the individual level, whereas morality was the strongest predictor of self-esteem at the collective level.


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