Microbial Activities and Dissolved Organic Matter Dynamics in Oil-Contaminated Surface Seawater from the Deepwater Horizon Oil Spill Site

The Deepwater Horizon oil spill triggered a complex cascade of microbial responses that reshaped the dynamics of heterotrophic carbon degradation and the turnover of dissolved organic carbon (DOC) in oil contaminated waters. Our results from 21-day laboratory incubations in rotating glass bottles (roller bottles) demonstrate that microbial dynamics and carbon flux in oil-contaminated surface water sampled near the spill site two weeks after the onset of the blowout were greatly affected by activities of microbes associated with macroscopic oil aggregates. Roller bottles with oil-amended water showed rapid formation of oil aggregates that were similar in size and appearance compared to oil aggregates observed in surface waters near the spill site. Oil aggregates that formed in roller bottles were densely colonized by heterotrophic bacteria, exhibiting high rates of enzymatic activity (lipase hydrolysis) indicative of oil degradation. Ambient waters surrounding aggregates also showed enhanced microbial activities not directly associated with primary oil-degradation (β-glucosidase; peptidase), as well as a twofold increase in DOC. Concurrent changes in fluorescence properties of colored dissolved organic matter (CDOM) suggest an increase in oil-derived, aromatic hydrocarbons in the DOC pool. Thus our data indicate that oil aggregates mediate, by two distinct mechanisms, the transfer of hydrocarbons to the deep sea: a microbially-derived flux of oil-derived DOC from sinking oil aggregates into the ambient water column, and rapid sedimentation of the oil aggregates themselves, serving as vehicles for oily particulate matter as well as oil aggregate-associated microbial communities

Interplay between CD8α+ Dendritic Cells and Monocytes in Response to Listeria monocytogenes Infection Attenuates T Cell Responses

During the course of a microbial infection, different antigen presenting cells (APCs) are exposed and contribute to the ensuing immune response. CD8α+ dendritic cells (DCs) are an important coordinator of early immune responses to the intracellular bacteria Listeria monocytogenes (Lm) and are crucial for CD8+ T cell immunity. In this study, we examine the contribution of different primary APCs to inducing immune responses against Lm. We find that CD8α+ DCs are the most susceptible to infection while plasmacytoid DCs are not infected. Moreover, CD8α+ DCs are the only DC subset capable of priming an immune response to Lm in vitro and are also the only APC studied that do so when transferred into β2 microglobulin deficient mice which lack endogenous cross-presentation. Upon infection, CD11b+ DCs primarily secrete low levels of TNFα while CD8α+ DCs secrete IL-12 p70. Infected monocytes secrete high levels of TNFα and IL-12p70, cytokines associated with activated inflammatory macrophages. Furthermore, co-culture of infected CD8α+ DCs and CD11b+ DCs with monocytes enhances production of IL-12 p70 and TNFα. However, the presence of monocytes in DC/T cell co-cultures attenuates T cell priming against Lm-derived antigens in vitro and in vivo. This suppressive activity of spleen-derived monocytes is mediated in part by both TNFα and inducible nitric oxide synthase (iNOS). Thus these monocytes enhance IL-12 production to Lm infection, but concurrently abrogate DC-mediated T cell priming

Applications of molecular communications to medicine: A survey

In recent years, progresses in nanotechnology have established the foundations for implementing nanomachines capable of carrying out simple but significant tasks. Under this stimulus, researchers have been proposing various solutions for realizing nanoscale communications, considering both electromagnetic and biological communications. Their aim is to extend the capabilities of nanodevices, so as to enable the execution of more complex tasks by means of mutual coordination, achievable through communications. However, although most of these proposals show how devices can communicate at the nanoscales, they leave in the background specific applications of these new technologies. Thus, this paper shows an overview of the actual and potential applications that can rely on a specific class of such communications techniques, commonly referred to as molecular communications. In particular, we focus on health-related applications. This decision is due to the rapidly increasing interests of research communities and companies to minimally invasive, biocompatible, and targeted health-care solutions. Molecular communication techniques have actually the potentials of becoming the main technology for implementing advanced medical solution. Hence, in this paper we provide a taxonomy of potential applications, illustrate them in some detail, along with the existing open challenges for them to be actually deployed, and draw future perspectives

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This crosscountry, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one's core values) or behavioral intentions. Results supported hypothesized associations between people's existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

Perivascular macrophages in health and disease

Macrophages are a heterogeneous group of cells that are capable of carrying out distinct functions in different tissues, as well as in different locations within a given tissue. Some of these tissue macrophages lie on, or close to, the outer (abluminal) surface of blood vessels and perform several crucial activities at this interface between the tissue and the blood. In steady-state tissues, these perivascular macrophages maintain tight junctions between endothelial cells and limit vessel permeability, phagocytose potential pathogens before they enter tissues from the blood and restrict inappropriate inflammation. They also have a multifaceted role in diseases such as cancer, Alzheimer disease, multiple sclerosis and type 1 diabetes. Here, we examine the important functions of perivascular macrophages in various adult tissues and describe how these functions are perturbed in a broad array of pathological conditions

A global experiment on motivating social distancing during the COVID-19 pandemic

Significance Communicating in ways that motivate engagement in social distancing remains a critical global public health priority during the COVID-19 pandemic. This study tested motivational qualities of messages about social distancing (those that promoted choice and agency vs. those that were forceful and shaming) in 25,718 people in 89 countries. The autonomy-supportive message decreased feelings of defying social distancing recommendations relative to the controlling message, and the controlling message increased controlled motivation, a less effective form of motivation, relative to no message. Message type did not impact intentions to socially distance, but people’s existing motivations were related to intentions. Findings were generalizable across a geographically diverse sample and may inform public health communication strategies in this and future global health emergencies. Abstract Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

Cross-slope variations of organic carbon and bacteria in the Gulf of Lions in relation to water dynamics (northwestern Mediterranean)

International audienceDuring November 1994,seawater samples were collected in the Gulf of Lions in the north- western Mediterranean Sea. Four stations were chosen to cover a range of environments, from coastal seawater near Marseille, France, to open ocean waters 30 miles off the coast. Samples were studied for dissolved and particulate organic carbon (DOC and POC) as well as bacterial abundance and chloro- phyll a (chl a) In the water column, DOC comprized 93 to 99% of total organic carbon, ranged from 65 to 118pM and was lower in deep waters on the slope. Considering an average 82 ~.IMDOC concen- tration measured In the surface layer (0 to 70 m) of the slope as typical of the core of the northwestern Mediterranean current, we estimated the DOC load carried by the current to range from 82 to 164 X to3 mol C S-', which was ca 100 times higher than the Rhone River input for the same period. Chl a con- centrations were up to 224 ng I-' whereas bacterial concentrations ranged from 0.9 to 7.7 X 10' cells ml-' making up 17 to 24% of the POC in the surface layer (0 to 70 m). Bacterial-C/phytoplankton-C ratios around the slope were higher than offshore and were in good agreement with bacterial production/ prlmary product~onratios. These results indicate a time lag between autotrophic phytoplanktonic and heterotroph~cbacterial activities and/or differences in the food web structure from the slope to the seaward end of the section. Although the bacterial-C/phytoplankton-C ratios were lower at the coastal station, the lowest primary production as well as higher bacterial production/primary production ratios were calculated in this area. This suggests that a part of bacterial production was sustained by terres- trial organic matter on the shelf Variations among stations sampled during comparable climatological conditions revealed the existence of a spatial gradient across the slope

Cross-slope variations of organic carbon and bacteria in the Gulf of Lions in relation to water dynamics (northwestern Mediterranean)

International audienceDuring November 1994,seawater samples were collected in the Gulf of Lions in the north- western Mediterranean Sea. Four stations were chosen to cover a range of environments, from coastal seawater near Marseille, France, to open ocean waters 30 miles off the coast. Samples were studied for dissolved and particulate organic carbon (DOC and POC) as well as bacterial abundance and chloro- phyll a (chl a) In the water column, DOC comprized 93 to 99% of total organic carbon, ranged from 65 to 118pM and was lower in deep waters on the slope. Considering an average 82 ~.IMDOC concen- tration measured In the surface layer (0 to 70 m) of the slope as typical of the core of the northwestern Mediterranean current, we estimated the DOC load carried by the current to range from 82 to 164 X to3 mol C S-', which was ca 100 times higher than the Rhone River input for the same period. Chl a con- centrations were up to 224 ng I-' whereas bacterial concentrations ranged from 0.9 to 7.7 X 10' cells ml-' making up 17 to 24% of the POC in the surface layer (0 to 70 m). Bacterial-C/phytoplankton-C ratios around the slope were higher than offshore and were in good agreement with bacterial production/ prlmary product~onratios. These results indicate a time lag between autotrophic phytoplanktonic and heterotroph~cbacterial activities and/or differences in the food web structure from the slope to the seaward end of the section. Although the bacterial-C/phytoplankton-C ratios were lower at the coastal station, the lowest primary production as well as higher bacterial production/primary production ratios were calculated in this area. This suggests that a part of bacterial production was sustained by terres- trial organic matter on the shelf Variations among stations sampled during comparable climatological conditions revealed the existence of a spatial gradient across the slope

Cross-slope variations of organic carbon and bacteria in the Gulf of Lions in relation to water dynamics (northwestern Mediterranean)

International audienceDuring November 1994,seawater samples were collected in the Gulf of Lions in the north- western Mediterranean Sea. Four stations were chosen to cover a range of environments, from coastal seawater near Marseille, France, to open ocean waters 30 miles off the coast. Samples were studied for dissolved and particulate organic carbon (DOC and POC) as well as bacterial abundance and chloro- phyll a (chl a) In the water column, DOC comprized 93 to 99% of total organic carbon, ranged from 65 to 118pM and was lower in deep waters on the slope. Considering an average 82 ~.IMDOC concen- tration measured In the surface layer (0 to 70 m) of the slope as typical of the core of the northwestern Mediterranean current, we estimated the DOC load carried by the current to range from 82 to 164 X to3 mol C S-', which was ca 100 times higher than the Rhone River input for the same period. Chl a con- centrations were up to 224 ng I-' whereas bacterial concentrations ranged from 0.9 to 7.7 X 10' cells ml-' making up 17 to 24% of the POC in the surface layer (0 to 70 m). Bacterial-C/phytoplankton-C ratios around the slope were higher than offshore and were in good agreement with bacterial production/ prlmary product~onratios. These results indicate a time lag between autotrophic phytoplanktonic and heterotroph~cbacterial activities and/or differences in the food web structure from the slope to the seaward end of the section. Although the bacterial-C/phytoplankton-C ratios were lower at the coastal station, the lowest primary production as well as higher bacterial production/primary production ratios were calculated in this area. This suggests that a part of bacterial production was sustained by terres- trial organic matter on the shelf Variations among stations sampled during comparable climatological conditions revealed the existence of a spatial gradient across the slope