Organic compounds drive growth in phytoplankton taxa from different functional groups.

Phytoplankton are usually considered autotrophs, but an increasing number of studies show that many taxa are able also to use organic carbon. Acquiring nutrients and energy from different sources might enable an efficient uptake of required substances and provide a strategy to deal with varying resource availability, especially in highly dynamic ecosystems such as estuaries. In our study, we investigated the effects of 31 organic carbon sources on the growth (proxied by differences in cell counts after 24 h exposure) of 17 phytoplankton strains from the Elbe estuary spanning four functional groups. All of our strains were able to make use of at least 1 and up to 26 organic compounds for growth. Pico-sized green algae such as Mychonastes, as well as the nano-sized green alga Monoraphidium in particular were positively affected by a high variety of substances. Reduced light availability, typically appearing in turbid estuaries and similar habitats, resulted in an overall poorer ability to use organic substances for growth, indicating that organic carbon acquisition was not primarily a strategy to deal with darkness. Our results give further evidence for mixotrophy being a ubiquitous ability of phytoplankton and highlight the importance to consider this trophic strategy in research.

Metabarcoding reveals potentially mixotrophic flagellates and picophytoplankton as key groups of phytoplankton in the Elbe estuary.

In estuaries, phytoplankton are faced with strong environmental forcing (e.g. high turbidity, salinity gradients). Taxa that appear under such conditions may play a critical role in maintaining food webs and biological carbon pumping, but knowledge about estuarine biota remains limited. This is also the case in the Elbe estuary where the lower 70 km of the water body are largely unexplored. In the present study, we investigated the phytoplankton composition in the Elbe estuary via metabarcoding. Our aim was to identify key taxa in the unmonitored reaches of this ecosystem and compare our results from the monitored area with available microscopy data. Phytoplankton communities followed distinct seasonal and spatial patterns. Community composition was similar across methods. Contributions of key classes and genera were correlated to each other (p < 0.05) when obtained from reads and biovolume (R2 = 0.59 and 0.33, respectively). Centric diatoms (e.g. Stephanodiscus) were the dominant group - comprising on average 55 % of the reads and 66-69 % of the biovolume. However, results from metabarcoding imply that microscopy underestimates the prevalence of picophytoplankton and flagellates with a potential for mixotrophy (e.g. cryptophytes). This might be due to their small size and sensitivity to fixation agents. We argue that mixotrophic flagellates are ecologically relevant in the mid to lower estuary, where, e.g., high turbidity render living conditions rather unfavorable, and skills such as phagotrophy provide fundamental advantages. Nevertheless, further findings - e.g. important taxa missing from the metabarcoding dataset - emphasize potential limitations of this method and quantitative biases can result from varying numbers of gene copies in different taxa. Further research should address these methodological issues but also shed light on the causal relationship of taxa with the environmental conditions, also with respect to active mixotrophic behavior.

Anticipated benefits and challenges of implementing group care in Suriname's maternity and child care sector: a contextual analysis.

BACKGROUND: Suriname is a uppermiddle-income country with a relatively high prevalence of preventable pregnancy complications. Access to and usage of high-quality maternity care services are lacking. The implementation of group care (GC) may yield maternal and child health improvements. However, before introducing a complex intervention it is pivotal to develop an understanding of the local context to inform the implementation process. METHODS: A context analysis was conducted to identify local needs toward maternity and postnatal care services, and to assess contextual factor relevant to implementability of GC. During a Rapid Qualitative Inquiry, 63 online and face-to-face semi-structured interviews were held with parents, community members, on-and off-site healthcare professionals, policy makers, and one focus group with parents was conducted. Audio recordings were transcribed in verbatim and analysed using thematic analysis and Framework Method. The Consolidated Framework for Implementation Research served as a base for the coding tree, which was complemented with inductively derived codes. RESULTS: Ten themes related to implementability, one theme related to sustainability, and seven themes related to reaching and participation of the target population in GC were identified. Factors related to health care professionals (e.g., workload, compatibility, ownership, role clarity), to GC, to recipients and to planning impact the implementability of GC, while sustainability is in particular hampered by sparse financial and human resources. Reach affects both implementability and sustainability. Yet, outer setting and attitudinal barriers of health professionals will likely affect reach. CONCLUSIONS: Multi-layered contextual factors impact not only implementability and sustainability of GC, but also reach of parents. We advise future researchers and implementors of GC to investigate not only determinants for implementability and sustainability, but also those factors that may hamper, or facilitate up-take. Practical, attitudinal and cultural barriers to GC participation need to be examined. Themes identified in this study will inspire the development of adaptations and implementation strategies at a later stage.

Group Care in the first 1000 days: implementation and process evaluation of contextually adapted antenatal and postnatal group care targeting diverse vulnerable populations in high-, middle- and low-resource settings.

BACKGROUND: Group care (GC) improves the quality of maternity care, stimulates women's participation in their own care and facilitates growth of women's social support networks. There is an urgent need to identify and disseminate the best mechanisms for implementing GC in ways that are feasible, context appropriate and sustainable. This protocol presents the aims and methods of an innovative implementation research project entitled Group Care in the first 1000 days (GC_1000), which addresses this need. AIMS: The aim of GC_1000 is to co-create and disseminate evidence-based implementation strategies and tools to support successful implementation and scale-up of GC in health systems throughout the world, with particular attention to the needs of 'vulnerable' populations. METHODS: By working through five inter-related work packages, each with specific tasks, objectives and deliverables, the global research team will systematically examine and document the implementation and scale-up processes of antenatal and postnatal GC in seven different countries. The GC_1000 project is grounded theoretically in the consolidated framework for implementation research (CFIR), while the process evaluation is guided by 'Realistic Evaluation' principles. Data are gathered across all research phases and analysis at each stage is synthesized to develop Context-Intervention-Mechanism-Outcome configurations. DISCUSSION: GC_1000 will generate evidence-based knowledge about the integration of complex interventions into diverse health care systems. The 4-year project also will pave the way for sustained implementation of GC, significantly benefitting populations with adverse pregnancy and birthing experiences as well as poor outcomes.

Suppressor of cytokine signaling 7 inhibits prolactin, growth hormone, and leptin signaling by interacting with STAT5 or STAT3 and attenuating their nuclear translocation.

We report here the role of one of the less studied members of the family of suppressors of cytokine signaling (SOCS), namely SOCS-7, in cytokine signaling. We demonstrate that SOCS-7 inhibits prolactin (PRL), growth hormone (GH), or leptin (LEP) signaling mediated through STAT3 and STAT5 in a dose-dependent manner. SOCS-7 also attenuated STAT3 and STAT5 signaling induced by overexpression of JH1, the catalytic subdomain of JAK2. Since SOCS-7 interacted with phosphorylated STAT3 or STAT5, we assumed that SOCS-7 acts at the level of STAT proteins. Indeed, we showed that SOCS-7 inhibits PRL- and leptin-induced STAT5 and STAT3 phosphorylation and prevented the nuclear translocation of activated STAT3. Taken together, our results indicate that SOCS-7 is a physiological dysregulator of PRL, leptin, and probably also GH signaling and that its mode of action is a novel variation of SOCS protein inhibition of cytokine-inducible STAT-mediated signal transduction.

Effects of prolactin on cloned human T-lymphocytes.

To evaluate the possible role of prolactin (PRL) in T-lymphocytes, we monitored gene induction in one cytotoxic T-lymphocyte (CTL) clone derived from a patient with hemochromatosis and in several T-helper clones generated from a normal donor and a patient with multiple sclerosis. The CTL clone expressed conventional PRL receptor (PRLR), and PRL induced the expression of suppressor of cytokine signaling-3 (SOCS-3) and increased the expression of SOCS-2 and cytokine-inducible src homology-2 containing protein (CIS, another member of the SOCS family). As is the case in granulocytes, expression of a conventional receptor for PRL could not be shown by polymerase chain reaction analysis on three helper clones. In addition, as in granulocytes, PRL modulated the expression of genes such as the interferon-regulatory factor-1, inducible nitric oxide synthase, CIS, and SOCS-2. These effects were also elicited with ovine PRL and could be prevented by anti-PRL antibodies. Thus, the use of clones allowed the detection of direct effects of PRL on T-cells, even when these have few or no detectable PRLR, confirming that human T-lymphocytes are targets for PRL.

The suppressor of cytokine signaling (SOCS)-7 interacts with the actin cytoskeleton through vinexin.

To understand the function of the suppressor of cytokine signaling (SOCS)-7, we have looked for proteins interacting with SOCS-7 in a stringent yeast two-hybrid screen of a human leukocyte cDNA-library. We identified the cytoskeletal molecule vinexin as a partner interacting with SOCS-7. Tests with deletion mutants of SOCS-7 demonstrated that a central region of the molecule containing several proline-rich regions, N-terminal to the SH2 domain, was responsible for the binding to vinexin. It is thus likely that one of the SH3 domains of vinexin interacts with a poly-proline region of SOCS-7. The interaction with vinexin was confirmed biochemically as vinexin-alpha was co-precipitated with SOCS-7. Confocal laser-scanning microscopy in HEK293T, MCF-7, and 3T3-L1 cells showed that part of the transfected SOCS-7-green fluorescent protein (GFP) molecules merged with vinexin and with actin. Taken together, our data indicate that SOCS-7 interacts with vinexin and the actin cytoskeleton.