Abstract
Staphylococcal food poisoning (SFP) is one of the most common food-borne diseases and results from the ingestion of staphylococcal enterotoxins (SEs) preformed in food by enterotoxigenic ...strains of Staphylococcus aureus. To date, more than 20 SEs have been described: SEA to SElV. All of them have superantigenic activity whereas half of them have been proved to be emetic, representing a potential hazard for consumers. This review, divided into four parts, will focus on the following: (1) the worldwide story of SFP outbreaks, (2) the characteristics and behaviour of S. aureus in food environment, (3) the toxinogenic conditions and characteristics of SEs, and (4) SFP outbreaks including symptomatology, occurrence in the European Union and currently available methods used to characterize staphylococcal outbreaks.
This review focuses on the importance of food poisonings due to staphylococcal enterotoxins: After a review of worldwide outbreaks due to coagulase positive staphylococci and their toxins, various parts such as characteristics and behavior of S. aureus in food environment, toxinogenic conditions and characteristics of staphylococcal enterotoxins, symptomatology, occurrence, reporting
system including European Union control and monitoring schemes are presented.
Milk and milk products can harbor a multiple varieties of microorganisms. Therefore, they can be an important source of foodborne pathogens, including multidrug‐resistant bacteria. ...Methicillin‐resistant Staphylococcus aureus (MRSA) causes a wide spectrum of infections both in animals and humans. Over the last two decades, the presence of MRSA in foods and food‐producing animals, including milk and milk products, has been frequently reported worldwide, raising public health concerns. In order to monitor and prevent foodborne MRSA contamination, it is necessary to understand their sources, the pheno/genotypic characteristics of the strains, and their transmission dynamics. In this review, studies conducted worldwide were summarized in order to assess the prevalence and diversity of MRSA circulating in milk and milk products. The risk factors for the occurrence of MRSA in milk and milk products were also discussed with preventive and control measures to avoid MRSA contamination in the dairy food chain.
Metabolism is controlled to ensure organismal development and homeostasis. Several mechanisms regulate metabolism, including allosteric control and transcriptional regulation of metabolic enzymes and ...transporters. So far, metabolism regulation has mostly been described for individual genes and pathways, and the extent of transcriptional regulation of the entire metabolic network remains largely unknown. Here, we find that three‐quarters of all metabolic genes are transcriptionally regulated in the nematode Caenorhabditis elegans. We find that many annotated metabolic pathways are coexpressed, and we use gene expression data and the iCEL1314 metabolic network model to define coregulated subpathways in an unbiased manner. Using a large gene expression compendium, we determine the conditions where subpathways exhibit strong coexpression. Finally, we develop “WormClust,” a web application that enables a gene‐by‐gene query of genes to view their association with metabolic (sub)‐pathways. Overall, this study sheds light on the ubiquity of transcriptional regulation of metabolism and provides a blueprint for similar studies in other organisms, including humans.
Synopsis
Systems‐level analyses in C. elegans show widespread transcriptional regulation of metabolic genes, coexpression of metabolic (sub)‐pathways, and activation/repression conditions of (sub)‐pathways.
Metabolic genes are transcriptionally regulated at a similar proportion as non‐metabolic genes.
Metabolic genes exhibit more transcriptional regulation in tissues than during development.
Metabolic pathways are frequently coexpressed.
A web application tool, WormClust http://wormflux.umassmed.edu/WormClust/wormclust.php, helps researchers find metabolic genes that are co‐expressed with a query gene.
Systems‐level analyses in C. elegans show widespread transcriptional regulation of metabolic genes, coexpression of metabolic (sub)‐pathways, and activation/repression conditions of (sub)‐pathways.
The appearance of multicellular organisms imposed the development of several mechanisms for cell-to-cell communication, whereby different types of cells coordinate their function. Some of these ...mechanisms depend on the intercellular diffusion of signal molecules in the extracellular spaces, whereas others require cell-to-cell contact. Among the latter mechanisms, those provided by the proteins of the connexin family are widespread in most tissues. Connexin signaling is achieved via direct exchanges of cytosolic molecules between adjacent cells at gap junctions, for cell-to-cell coupling, and possibly also involves the formation of membrane "hemi-channels," for the extracellular release of cytosolic signals, direct interactions between connexins and other cell proteins, and coordinated influence on the expression of multiple genes. Connexin signaling appears to be an obligatory attribute of all multicellular exocrine and endocrine glands. Specifically, the experimental evidence we review here points to a direct participation of the Cx36 isoform in the function of the insulin-producing β-cells of the endocrine pancreas, and of the Cx40 isoform in the function of the renin-producing juxtaglomerular epithelioid cells of the kidney cortex.
Among heterosexual couples, employment of the female partner may suffer from household migration often driven by the job of the male partner. Most research has traditionally focused on the distance ...moved after couple formation and has neglected how far partners live from their birthplaces. Recent life course research has shown that staying in, leaving or returning to the place of origin of one or both partners often reflects couples' work–family arrangements. This study contributes to this literature by examining the division of employment between partners and their relative contribution to household income according to migration distances. We analyse data from a national sample of economically active individuals living with heterosexual partners in Switzerland. When controlling for selectivity of migrant couples, the analysis confirms that long‐distance household migration benefits men's relative earnings. Among couples who migrated within the same region, employment is more equally shared between partners than among other couples, including nonmigrant couples. The relative distance to birthplaces also matters. Women's contribution to household income is higher among couples in which men migrated close to women's birthplace and is lower among couples where women migrated close to men's birthplace compared to women in other couples. This study suggests that future research on household migration should consider important social ties and places beyond the ‘last family move’ and the mechanisms by which these ties and places influence couples' decisions about where to live together and economic outcomes.
Combining single‐cell measurements of ERK activity dynamics with perturbations provides insights into the MAPK network topology. We built circuits consisting of an optogenetic actuator to activate ...MAPK signaling and an ERK biosensor to measure single‐cell ERK dynamics. This allowed us to conduct RNAi screens to investigate the role of 50 MAPK proteins in ERK dynamics. We found that the MAPK network is robust against most node perturbations. We observed that the ERK‐RAF and the ERK‐RSK2‐SOS negative feedback operate simultaneously to regulate ERK dynamics. Bypassing the RSK2‐mediated feedback, either by direct optogenetic activation of RAS, or by RSK2 perturbation, sensitized ERK dynamics to further perturbations. Similarly, targeting this feedback in a human ErbB2‐dependent oncogenic signaling model increased the efficiency of a MEK inhibitor. The RSK2‐mediated feedback is thus important for the ability of the MAPK network to produce consistent ERK outputs, and its perturbation can enhance the efficiency of MAPK inhibitors.
Synopsis
MAPK signaling involves a complex network of interacting nodes, whose role in shaping ERK dynamics remains largely unknown. Optogenetic actuator‐ERK biosensor circuits combined with RNAi perturbations highlight specific nodes that regulate ERK dynamics.
Genetic circuits consisting of optogenetic actuators and an ERK biosensor enable large‐scale interrogation of single‐cell ERK dynamics.
RNAi perturbations of 50 MAPK nodes provide new insight into MAPK network circuitry.
Two negative feedbacks within the MAPK network act simultaneously in the regulation of ERK dynamics.
Perturbation of one of the negative feedbacks further potentiates RAF/MEK/ERK node inhibition leading to homogeneous suppression of ERK dynamics within a cell population.
MAPK signaling involves a complex network of interacting nodes, whose role in shaping ERK dynamics remains largely unknown. Optogenetic actuator‐ERK biosensor circuits combined with RNAi perturbations highlight specific nodes that regulate ERK dynamics.
Cell death events continuously challenge epithelial barrier function yet are crucial to eliminate old or critically damaged cells. How such apoptotic events are spatio-temporally organized to ...maintain epithelial homeostasis remains unclear. We observe waves of extracellular-signal-regulated kinase (ERK) and AKT serine/threonine kinase (Akt) activity pulses that originate from apoptotic cells and propagate radially to healthy surrounding cells. This requires epidermal growth factor receptor (EGFR) and matrix metalloproteinase (MMP) signaling. At the single-cell level, ERK/Akt waves act as spatial survival signals that locally protect cells in the vicinity of the epithelial injury from apoptosis for a period of 3–4 h. At the cell population level, ERK/Akt waves maintain epithelial homeostasis (EH) in response to mild or intense environmental insults. Disruption of this spatial signaling system results in the inability of a model epithelial tissue to ensure barrier function in response to environmental insults.
Display omitted
•Apoptotic epithelial cells trigger ERK/Akt activity waves in their neighboring cells•EGFR and metalloprotease signaling is required for the ERK/Akt activity wave•Such a signaling wave induces 3–4 h of survival in the neighboring cells•ERK/Akt waves maintain epithelial integrity in response to environmental insults
How do epithelia dynamically maintain their integrity in a constantly changing environment? Gagliardi et al. show that apoptotic cells trigger ERK/Akt waves in their neighboring cells inducing survival for 3–4 h. At the cell population scale, this mechanism dynamically protects the epithelium from mild to acute environmental insults.
Bacillus cereus is responsible for foodborne outbreaks worldwide. Among the produced toxins, cereulide induces nausea and vomiting after 30 min to 6 h following the consumption of contaminated foods. ...Cereulide, a cyclodepsipeptide, is an ionophore selective to K+ in solution. In electrospray, the selectivity is reduced as M + Li+; M + Na+ and M + NH4+ can also be detected without adding corresponding salts. Two forms are possible for alkali‐cationized ions: charge‐solvated (CS) that exclusively dissociates by releasing a bare alkali ion and protonated salt (PS), yielding alkali product ions by covalent bond cleavages (CBC) promoted by mobile proton. Based on a modified peptide cleavage nomenclature, the PS product ion series (b, a, b + H2O and b + CnH2nO n = 4, 5) are produced by Na+/Li+/K+‐cationized cereulide species that specifically open at ester linkages followed by proton mobilization promoting competitive ester CBC as evidenced under resonant collision activation. What is more, unlike the sodiated or lithiated cereulide, which regenerates little or no alkali cation, the potassiated forms lead to an abundant K+ regeneration. This occurs by splitting of (i) the potassiated CS forms with an appearance threshold close to that of the PS first fragment ion generation and (ii) eight to four potassiated residue product ions from the PS forms. Since from Na+/Li+‐cationized cereulide, (i) the negligible Na+/Li+ regeneration results in a higher sensibility than that of potassiated forms that abundantly releasing K+, and (ii) a better sequence recovering, the use of Na+ (or Li+) should be more pertinent to sequence isocereulides and other cyclodepsipeptides.
Individual life courses are marked by residential mobility often associated with family and workplace changes and therefore likely to be related to the types of personal relationships people develop ...and maintain. Evidence about the relationship between residential mobility behaviours over the life course and personal network composition is however scarce. This study investigates this relationship among 747 individuals living in Switzerland using regression models and standard deviational ellipse for analysing all residential locations in Switzerland and their duration over the life course. Results show that people with low residential mobility have personal networks centred around the partner and vertical family ties (parents and children), confirming that strong intergenerational ties develop in close proximity. By contrast, longer distance residential moves at the regional level are associated with small personal networks centred around peers and horizontal ties (such as friends and siblings). The network composition of people with mobility experiences at the national level does not differ from the network composition of non‐movers when controlling for socio‐demographic characteristics. Likewise, networks including in‐laws and extended family members and large mixed networks including both family and friends were not associated with a particular residential mobility trajectory. The density of the Swiss transport system enabling people to stay connected to family and friends may partly explain the weak association between residential mobility behaviours and the composition of personal networks.
The aim of the thematic issue Family Supportive Networks and Practices in Vulnerable Contexts is to provide a cross‐national perspective on the current state of caregiving and support practices ...within family networks in Europe. The articles featured in this volume were selected from among the presentations made in 2021 at two conferences promoted by the research network Sociology of Families and Intimate Lives of the European Sociological Association (ESA RN13). Authors of the most promising, topical, and up‐to‐date research papers were invited to contribute to this thematic issue.
PDF
