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  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 21 April 2015, Vol.112(16), pp.5159-64
    Description: RpoS, the stationary phase/stress sigma factor of Escherichia coli, regulates a large cohort of genes important for the cell to deal with suboptimal conditions. Its level increases quickly in the cell in response to many stresses and returns to low levels when growth resumes. Increased RpoS results from increased translation and decreased RpoS degradation. Translation is positively regulated by small RNAs (sRNAs). Protein stability is positively regulated by anti-adaptors, which prevent the RssB adaptor-mediated degradation of RpoS by the ClpXP protease. Inactivation of aceE, a subunit of pyruvate dehydrogenase (PDH), was found to increase levels of RpoS by affecting both translation and protein degradation. The stabilization of RpoS in aceE mutants is dependent on increased transcription and translation of IraP and IraD, two known anti-adaptors. The aceE mutation also leads to a significant increase in rpoS translation. The sRNAs known to positively regulate RpoS are not responsible for the increased translation; sequences around the start codon are sufficient for the induction of translation. PDH synthesizes acetyl-CoA; acetate supplementation allows the cell to synthesize acetyl-CoA by an alternative, less favored pathway, in part dependent upon RpoS. Acetate addition suppressed the effects of the aceE mutant on induction of the anti-adaptors, RpoS stabilization, and rpoS translation. Thus, the bacterial cell responds to lowered levels of acetyl-CoA by inducing RpoS, allowing reprogramming of E. coli metabolism.
    Keywords: Clpxp ; Rpos ; Rssb ; Acetyl Coa ; Pyruvate Dehydrogenase ; Protein Biosynthesis ; Proteolysis ; Stress, Physiological ; Bacterial Proteins -- Metabolism ; Escherichia Coli -- Metabolism ; Sigma Factor -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 2
    Language: English
    In: Current Biology, 21 February 2012, Vol.22(4), pp.309-313
    Description: Understanding how behavioral diversity arises and is maintained is central to evolutionary biology. Genetically based inheritance has been a predominant research focus of the last century; however, nongenetic inheritance, such as social transmission, has become a topic of increasing interest [ ]. How social information impacts behavior depends on the balance between information gathered directly through personal experience versus that gleaned through social interactions and on the diffusion of this information within groups [ ]. We investigate how female use social information under seminatural conditions and whether this information can spread and be maintained within a group, a prerequisite for establishing behavioral transmission [ ]. We show that oviposition site choice is heavily influenced by previous social interactions. Naive observer flies develop a preference for the same egg-laying medium as experienced demonstrator flies conditioned to avoid one of two equally rewarding media. Surprisingly, oviposition site preference was socially transmitted from demonstrators to observers even when they interacted in a cage with only unflavored, pure agar medium, and even when the observer flies had previous personal experience with both rewarding media. Our findings shed light on the diffusion process of social information within groups, on its maintenance, and ultimately, on the roots of behavioral local adaptation. ► Naive females gain information about where to lay eggs from experienced females ► Naive females do not learn from cues like egg number or pheromones ► Naive females do not require direct experience with the options to make a decision ► Social information can spread and be maintained within a group
    Keywords: Biology
    ISSN: 0960-9822
    E-ISSN: 1879-0445
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  • 3
    Language: English
    In: Journal of Bacteriology, May, 2012, Vol.194(9-10), p.2470(8)
    Description: RpoS, the master sigma factor during stationary phase and under a variety of stress conditions, is regulated at multiple levels, including regulated degradation. Degradation is dependent upon ClpXP and the RssB adaptor protein. H-NS, a nucleoid-associated protein, affects the regulated degradation of RpoS; in the absence of H-NS, RpoS is stable. The mechanisms involved in this regulation were not known. We have found that H-NS inhibits the expression of iraD and iraM, the genes coding for two antiadaptor proteins that stabilize RpoS when overexpressed. The regulation by H-NS of iraM is independent from the previously demonstrated regulation by the PhoP/PhoQ two-component system. Moreover, differences in the behavior of several hns alleles are explained by a role for StpA, an H-NS-like protein, in the regulation of RpoS stability. This finding parallels recent observations for a role of StpA in regulation of RpoS stability in Salmonella.
    Keywords: Salmonella -- Genetic Aspects ; Transcription Factors -- Chemical Properties ; Transcription (Genetics) -- Research ; Gene Expression -- Analysis
    ISSN: 0021-9193
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: The International Journal of Human Resource Management, 01 March 2013, Vol.24(6), pp.1300-1321
    Description: This paper examines workers' satisfaction related to the level of professionalism of managerial practices in the French services sector. The data used are from the original survey conducted by the French Institute for Demographic Research and include both workers' responses on their satisfaction...
    Keywords: Management Practices ; Nonprofits ; Satisfaction ; Services Sector ; Business ; Economics
    ISSN: 0958-5192
    E-ISSN: 1466-4399
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  • 5
    Language: English
    In: Behavioral Ecology and Sociobiology, 2015, Vol.69(1), pp.83-87
    Description: Within a group, animals adjust individual decisions to environmental conditions both through their own experience and by interacting with other animals. How individuals balance social vs. personal information may have a deep impact on their fitness, and this might be particularly relevant when individuals interact with conspecifics that carry different, or even conflicting, information. In animals, conformist strategy of social learning, defined by the tendency of individuals to disproportionately adopt the most commonly encountered social information, appears to be more widespread than previously thought. Here, we investigated whether females of the fruit fly, Drosophila melanogaster , conform their oviposition site choice to social cues coming from conspecifics. Groups of naïve “observer” flies were exposed to two oviposition media (banana or strawberry flavored) and to other “demonstrator” flies that were previously trained to prefer one of the two media. All flies were then tested for their oviposition preference. The preference of observer flies was highly sensitive to the social composition of the demonstrator group, and even the presence of a small proportion of individuals trained to oviposit on banana was enough to induce a biased preference for the banana medium. Our results suggest that D. melanogaster females combine their personal preference with social information to choose oviposition sites rather than showing social conformity.
    Keywords: Drosophila ; Frequency-dependent bias ; Oviposition
    ISSN: 0340-5443
    E-ISSN: 1432-0762
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  • 6
    Language: English
    In: Food Chemistry, 01 September 2012, Vol.134(1), pp.37-47
    Description: ► “Spring maquis” honeys were characterized by 50 characteristic pollen taxa. was the over-represented taxon. ► Main compounds of flowers were octen-3-ol, - and - -ocimene. ► Main components of honeys were 4- -propylanisol, -anisaldehyde and benzaldehyde. ► Frequency of pollen was correlated with honey aromatic intensity. Melissopalynology and volatiles’ analysis are applied for origin identification of 45 Corsican “spring maquis” honeys, regionally representative of this Protected Denomination of Origin “Miel de Corse–Mele di Corsica” range. They are dominated by pollens. Studies of statistical distribution, biogeographical typology and altitudinal distribution of the 50 characteristic taxa certify the Corsican origin of these honeys. The volatile fraction extracted by headspace solid-phase microextraction (HS-SPME) from Corsican . flowers was dominated by octen-3-ol, ( ) -ocimene and ( ) -ocimene whereas 4-propylanisol, -anisaldehyde, benzaldehyde and 3-furaldehyde were identified as the main volatile components of Corsican honeys. Taking into account the volatile fraction and melissopalynological and physicochemical data, cluster analysis and principal component analysis highlighted the correlation between the relative frequency of . pollens, the total peak areas of spring maquis honeys and the amounts of -anisaldehyde and 4-propylanisol.
    Keywords: Corsican “erica Arborea Spring Maquis” Honey ; E. Arborea Flowers ; Melissopalynological Analysis ; Hs-Spme–Gc–Fid and Hs-Spme–Gc–MS ; Statistical Analysis ; Chemistry ; Diet & Clinical Nutrition ; Economics
    ISSN: 0308-8146
    E-ISSN: 1873-7072
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  • 7
    Language: English
    In: Journal of Bacteriology, Jan, 2009, Vol.191(1-2), p.616(9)
    Description: Bacteria respond to nutritional stress by producing (p)ppGpp, which triggers a stringent response resulting in growth arrest and expression of resistance genes. In Escherichia coli, RelA produces (p)ppGpp upon amino acid starvation by detecting stalled ribosomes. The SpoT enzyme responds to various other types of starvation by unknown mechanisms. We previously described an interaction between SpoT and the central cofactor of lipid synthesis, acyl carrier protein (ACP), which is involved in detecting starvation signals in lipid metabolism and triggering SpoT-dependent (p)ppGpp accumulation. However, most bacteria possess a unique protein homologous to RelA/SpoT (Rsh) that is able to synthesize and degrade (p)ppGpp and is therefore more closely related to SpoT function. In this study, we asked if the ACP-SpoT interaction is specific for bacteria containing two RelA and SpoT enzymes or if it is a general feature that is conserved in Rsh enzymes. By testing various combinations of SpoT, RelA, and Rsh enzymes and ACPs of E. coli, Pseudomonas aeruginosa, Bacillus subtilis and Streptococcus pneumoniae, we found that the interaction between (p)ppGpp synthases and ACP seemed to be restricted to SpoT proteins of bacteria containing the two RelA and SpoT proteins and to ACP proteins encoded by genes located in fatty acid synthesis operons. When Rsh enzymes from B. subtilis and S. pneumoniae are produced in E. coli, the behavior of these enzymes is different from the behavior of both RelA and SpoT proteins with respect to (p)ppGpp synthesis. This suggests that bacteria have evolved several different modes of (p)ppGpp regulation in order to respond to nutrient starvation.
    Keywords: Bacterial Proteins -- Properties ; Escherichia Coli -- Genetic Aspects ; Escherichia Coli -- Physiological Aspects
    ISSN: 0021-9193
    Source: Cengage Learning, Inc.
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  • 8
    Language: English
    In: Current Opinion in Microbiology, April 2013, Vol.16(2), pp.140-147
    Description: ► Regulated degradation by ATP-dependent proteases frequently depends upon delivery of the substrate by adaptors. ► Regulation of activity of adaptors by anti-adaptors allows environmental modulation of protein turnover. ► Structural studies are uncovering how adaptors bind and hand over the substrate to the protease. Elimination of non-functional or unwanted proteins is critical for cell growth and regulation. In bacteria, ATP-dependent proteases target cytoplasmic proteins for degradation, contributing to both protein quality control and regulation of specific proteins, thus playing roles parallel to that of the proteasome in eukaryotic cells. Adaptor proteins provide a way to modulate the substrate specificity of the proteases and allow regulated proteolysis. Advances over the past few years have provided new insight into how adaptor proteins interact with both substrates and proteases and how adaptor functions are regulated. An important advance has come with the recognition of the critical roles of anti-adaptor proteins in regulating adaptor availability.
    Keywords: Biology
    ISSN: 1369-5274
    E-ISSN: 1879-0364
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  • 9
    Language: English
    In: Methods, December 2012, Vol.58(4), pp.325-334
    Description: The bacterial two-hybrid system based on the reconstitution of adenylate cyclase in (BACTH) was described 14 years ago (Karimova, Pidoux, Ullmann, and Ladant, 1998, PNAS, 95:5752). For microbiologists, it is a practical and powerful alternative to the use of the widely spread yeast two-hybrid technology for testing protein–protein interactions. In this review, we aim at giving the reader clear and most importantly simple instructions that should break any reticence to try the technique. Yet, we also add recommendations in the use of the system, related to its specificities. Finally, we expose the advantages and disadvantages of the technique, and review its diverse applications in the literature, which should help in deciding if it is the appropriate method to choose for the case at hand.
    Keywords: Protein–Protein Interaction ; Two-Hybrid ; Escherichia Coli ; Adenylate Cyclase ; Calmodulin ; Β-Galactosidase Assay ; Chemistry ; Anatomy & Physiology
    ISSN: 1046-2023
    E-ISSN: 1095-9130
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  • 10
    Language: English
    In: Frontiers of neurology and neuroscience, 2016, Vol.38, pp.132-42
    Description: People died from nostalgia in the army in the 17th-19th centuries. The term 'nostalgia', created by the doctor Johannes Hofer (1669-1752), from Mulhouse, came from the Germanic Heimweh, or 'homesickness'. It affected the young people enrolled in the army, such as Swiss mercenaries. Longing for their native land, they were consumed by an ongoing desire to return home. If it was impossible to do so, they sank into 'a sadness accompanied with insomnia, anorexia and other unpleasant symptoms' that could lead to death. Nostalgia became classified as a disease during the last quarter of the 18th century and ravaged the French army during the Revolution and the Napoleonic wars. However, as soon as the wars ended, it ceased to exist in the army (except the colonial army). It was removed from the nosology in the first half of the 19th century. Rapidly explained as an example of a misdiagnosis or a confusion between 'connection and cause', nostalgia needs to be assessed in regard to the medical debate between 'alienists' and 'organicists'. Creating much concern, nostalgia needs to be considered in the historical context of a society destabilized by modernity, with some individuals uprooted by the sudden transition from civil society to military life. It raises questions about the role that the army played in the creation of the French national union. Nostalgia may have also covered psychic traumatisms later designated as combat fatigue, war neurosis, or post-traumatic stress disorder.
    Keywords: Combat Disorders -- History ; Military Personnel -- History ; Paintings -- History
    ISSN: 16604431
    E-ISSN: 1662-2804
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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