High Yield of Adult Oligodendrocyte Lineage Cells Obtained from Meningeal Biopsy

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Sissi Dolci

2017-10-01

Full Text Available Oligodendrocyte loss can lead to cognitive and motor deficits. Current remyelinating therapeutic strategies imply either modulation of endogenous oligodendrocyte precursors or transplantation of in vitro expanded oligodendrocytes. Cell therapy, however, still lacks identification of an adequate source of oligodendrocyte present in adulthood and able to efficiently produce transplantable cells. Recently, a neural stem cell-like population has been identified in meninges. We developed a protocol to obtain high yield of oligodendrocyte lineage cells from one single biopsy of adult rat meningeal tissue. From 1 cm2 of adult rat spinal cord meninges, we efficiently expanded a homogenous culture of 10 millions of meningeal-derived oligodendrocyte lineage cells in a short period of time (approximately 4 weeks. Meningeal-derived oligodendrocyte lineage cells show typical mature oligodendrocyte morphology and express specific oligodendrocyte markers, such as galactosylceramidase and myelin basic protein. Moreover, when transplanted in a chemically demyelinated spinal cord model, meningeal-derived oligodendrocyte lineage cells display in vivo-remyelinating potential. This oligodendrocyte lineage cell population derives from an accessible and adult source, being therefore a promising candidate for autologous cell therapy of demyelinating diseases. In addition, the described method to differentiate meningeal-derived neural stem cells into oligodendrocyte lineage cells may represent a valid in vitro model to dissect oligodendrocyte differentiation and to screen for drugs capable to promote oligodendrocyte regeneration.

Cytomegalovirus immune evasion of myeloid lineage cells.

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Brinkmann, Melanie M; Dağ, Franziska; Hengel, Hartmut; Messerle, Martin; Kalinke, Ulrich; Čičin-Šain, Luka

2015-06-01

Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.

Lineage Switching in Acute Leukemias: A Consequence of Stem Cell Plasticity?

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Elisa Dorantes-Acosta

2012-01-01

Full Text Available Acute leukemias are the most common cancer in childhood and characterized by the uncontrolled production of hematopoietic precursor cells of the lymphoid or myeloid series within the bone marrow. Even when a relatively high efficiency of therapeutic agents has increased the overall survival rates in the last years, factors such as cell lineage switching and the rise of mixed lineages at relapses often change the prognosis of the illness. During lineage switching, conversions from lymphoblastic leukemia to myeloid leukemia, or vice versa, are recorded. The central mechanisms involved in these phenomena remain undefined, but recent studies suggest that lineage commitment of plastic hematopoietic progenitors may be multidirectional and reversible upon specific signals provided by both intrinsic and environmental cues. In this paper, we focus on the current knowledge about cell heterogeneity and the lineage switch resulting from leukemic cells plasticity. A number of hypothetical mechanisms that may inspire changes in cell fate decisions are highlighted. Understanding the plasticity of leukemia initiating cells might be fundamental to unravel the pathogenesis of lineage switch in acute leukemias and will illuminate the importance of a flexible hematopoietic development.

Ascl1 (Mash1) lineage cells contribute to discrete cell populations in CNS architecture

OpenAIRE

Kim, Euiseok J.; Battiste, James; Nakagawa, Yasushi; Johnson, Jane E.

2008-01-01

Ascl1 (previously Mash1) is a bHLH transcription factor essential for neuronal differentiation and specification in the nervous system. Although it has been studied for its role in several neural lineages, the full complement of lineages arising from Ascl1 progenitor cells remains unknown. Using an inducible Cre-flox genetic fate mapping strategy, Ascl1 lineages were determined throughout the brain. Ascl1 is present in proliferating progenitor cells but these cells are actively differentiatin...

Tissue-resident natural killer (NK) cells are cell lineages distinct from thymic and conventional splenic NK cells

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Sojka, Dorothy K; Plougastel-Douglas, Beatrice; Yang, Liping; Pak-Wittel, Melissa A; Artyomov, Maxim N; Ivanova, Yulia; Zhong, Chao; Chase, Julie M; Rothman, Paul B; Yu, Jenny; Riley, Joan K; Zhu, Jinfang; Tian, Zhigang; Yokoyama, Wayne M

2014-01-01

Natural killer (NK) cells belong to the innate immune system; they can control virus infections and developing tumors by cytotoxicity and producing inflammatory cytokines. Most studies of mouse NK cells, however, have focused on conventional NK (cNK) cells in the spleen. Recently, we described two populations of liver NK cells, tissue-resident NK (trNK) cells and those resembling splenic cNK cells. However, their lineage relationship was unclear; trNK cells could be developing cNK cells, related to thymic NK cells, or a lineage distinct from both cNK and thymic NK cells. Herein we used detailed transcriptomic, flow cytometric, and functional analysis and transcription factor-deficient mice to determine that liver trNK cells form a distinct lineage from cNK and thymic NK cells. Taken together with analysis of trNK cells in other tissues, there are at least four distinct lineages of NK cells: cNK, thymic, liver (and skin) trNK, and uterine trNK cells. DOI: http://dx.doi.org/10.7554/eLife.01659.001 PMID:24714492

Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells.

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Miranda, Ana F; Taha, Mohamed; Wrede, Digby; Morrison, Paul; Ball, Andrew S; Stevenson, Trevor; Mouradov, Aidyn

2015-01-01

Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive. This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its genetically modified derivatives that have been altered to enable secretion of free fatty acids into growth media. Secreted free fatty acids are potentially used by fungal cells as a carbon source for growth and ex-novo production of lipids. For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures. The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus. Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

Single cell lineage analysis of mouse embryonic stem cells at the exit from pluripotency

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Jamie Trott

2013-08-01

Understanding how interactions between extracellular signalling pathways and transcription factor networks influence cellular decision making will be crucial for understanding mammalian embryogenesis and for generating specialised cell types in vitro. To this end, pluripotent mouse Embryonic Stem (mES cells have proven to be a useful model system. However, understanding how transcription factors and signalling pathways affect decisions made by individual cells is confounded by the fact that measurements are generally made on groups of cells, whilst individual mES cells differentiate at different rates and towards different lineages, even in conditions that favour a particular lineage. Here we have used single-cell measurements of transcription factor expression and Wnt/β-catenin signalling activity to investigate their effects on lineage commitment decisions made by individual cells. We find that pluripotent mES cells exhibit differing degrees of heterogeneity in their expression of important regulators from pluripotency, depending on the signalling environment to which they are exposed. As mES cells differentiate, downregulation of Nanog and Oct4 primes cells for neural commitment, whilst loss of Sox2 expression primes cells for primitive streak commitment. Furthermore, we find that Wnt signalling acts through Nanog to direct cells towards a primitive streak fate, but that transcriptionally active β-catenin is associated with both neural and primitive streak commitment. These observations confirm and extend previous suggestions that pluripotency genes influence lineage commitment and demonstrate how their dynamic expression affects the direction of lineage commitment, whilst illustrating two ways in which the Wnt signalling pathway acts on this network during cell fate assignment.

Ascl1 (Mash1) lineage cells contribute to discrete cell populations in CNS architecture.

Science.gov (United States)

Kim, Euiseok J; Battiste, James; Nakagawa, Yasushi; Johnson, Jane E

2008-08-01

Ascl1 (previously Mash1) is a bHLH transcription factor essential for neuronal differentiation and specification in the nervous system. Although it has been studied for its role in several neural lineages, the full complement of lineages arising from Ascl1 progenitor cells remains unknown. Using an inducible Cre-flox genetic fate-mapping strategy, Ascl1 lineages were determined throughout the brain. Ascl1 is present in proliferating progenitor cells but these cells are actively differentiating as evidenced by rapid migration out of germinal zones. Ascl1 lineage cells contribute to distinct cell types in each major brain division: the forebrain including the cerebral cortex, olfactory bulb, hippocampus, striatum, hypothalamus, and thalamic nuclei, the midbrain including superior and inferior colliculi, and the hindbrain including Purkinje and deep cerebellar nuclei cells and cells in the trigeminal sensory system. Ascl1 progenitor cells at early stages in each CNS region preferentially become neurons, and at late stages they become oligodendrocytes. In conclusion, Ascl1-expressing progenitor cells in the brain give rise to multiple, but not all, neuronal subtypes and oligodendrocytes depending on the temporal and spatial context, consistent with a broad role in neural differentiation with some subtype specification.

Genome-Nuclear Lamina Interactions Regulate Cardiac Stem Cell Lineage Restriction.

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Poleshko, Andrey; Shah, Parisha P; Gupta, Mudit; Babu, Apoorva; Morley, Michael P; Manderfield, Lauren J; Ifkovits, Jamie L; Calderon, Damelys; Aghajanian, Haig; Sierra-Pagán, Javier E; Sun, Zheng; Wang, Qiaohong; Li, Li; Dubois, Nicole C; Morrisey, Edward E; Lazar, Mitchell A; Smith, Cheryl L; Epstein, Jonathan A; Jain, Rajan

2017-10-19

Progenitor cells differentiate into specialized cell types through coordinated expression of lineage-specific genes and modification of complex chromatin configurations. We demonstrate that a histone deacetylase (Hdac3) organizes heterochromatin at the nuclear lamina during cardiac progenitor lineage restriction. Specification of cardiomyocytes is associated with reorganization of peripheral heterochromatin, and independent of deacetylase activity, Hdac3 tethers peripheral heterochromatin containing lineage-relevant genes to the nuclear lamina. Deletion of Hdac3 in cardiac progenitor cells releases genomic regions from the nuclear periphery, leading to precocious cardiac gene expression and differentiation into cardiomyocytes; in contrast, restricting Hdac3 to the nuclear periphery rescues myogenesis in progenitors otherwise lacking Hdac3. Our results suggest that availability of genomic regions for activation by lineage-specific factors is regulated in part through dynamic chromatin-nuclear lamina interactions and that competence of a progenitor cell to respond to differentiation signals may depend upon coordinated movement of responding gene loci away from the nuclear periphery. Copyright © 2017 Elsevier Inc. All rights reserved.

Ezh2 represses the basal cell lineage during lung endoderm development.

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Snitow, Melinda E; Li, Shanru; Morley, Michael P; Rathi, Komal; Lu, Min Min; Kadzik, Rachel S; Stewart, Kathleen M; Morrisey, Edward E

2015-01-01

The development of the lung epithelium is regulated in a stepwise fashion to generate numerous differentiated and stem cell lineages in the adult lung. How these different lineages are generated in a spatially and temporally restricted fashion remains poorly understood, although epigenetic regulation probably plays an important role. We show that the Polycomb repressive complex 2 component Ezh2 is highly expressed in early lung development but is gradually downregulated by late gestation. Deletion of Ezh2 in early lung endoderm progenitors leads to the ectopic and premature appearance of Trp63+ basal cells that extend the entire length of the airway. Loss of Ezh2 also leads to reduced secretory cell differentiation. In their place, morphologically similar cells develop that express a subset of basal cell genes, including keratin 5, but no longer express high levels of either Trp63 or of standard secretory cell markers. This suggests that Ezh2 regulates the phenotypic switch between basal cells and secretory cells. Together, these findings show that Ezh2 restricts the basal cell lineage during normal lung endoderm development to allow the proper patterning of epithelial lineages during lung formation. © 2015. Published by The Company of Biologists Ltd.

Involvement of multiple cell lineages in atherogenesis | Ogeng'o ...

African Journals Online (AJOL)

Involvement of multiple cell lineages in atherogenesis. ... mast cells, dendritic cells, macrophages and immigrant cells usually found in blood, namely ... which influence inflammation, migration, proliferation and secretory activity of each other in ...

Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins

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Miquel Lürling

2017-02-01

Full Text Available Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C with and without additional nutrients added (eutrophication mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll-a and 25 times more eukaryote algal chlorophyll-a. At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll-a being 17 times and eukaryote algal chlorophyll-a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis. This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance.

Two subpopulations of stem cells for T cell lineage

International Nuclear Information System (INIS)

Katsura, Y.; Amagai, T.; Kina, T.; Sado, T.; Nishikawa, S.

1985-01-01

An assay system for the stem cell that colonizes the thymus and differentiates into T cells was developed, and by using this assay system the existence of two subpopulations of stem cells for T cell lineage was clarified. Part-body-shielded and 900-R-irradiated C57BL/6 (H-2b, Thy-1.2) recipient mice, which do not require the transfer of pluripotent stem cells for their survival, were transferred with cells from B10 X Thy-1.1 (H-2b, Thy-1.1) donor mice. The reconstitution of the recipient's thymus lymphocytes was accomplished by stem cells in the donor cells and those spared in the shielded portion of the recipient that competitively colonize the thymus. Thus, the stem cell activity of donor cells can be evaluated by determining the proportion of donor-type (Thy-1.1+) cells in the recipient's thymus. Bone marrow cells were the most potent source of stem cells. By contrast, when the stem cell activity was compared between spleen and bone marrow cells of whole-body-irradiated (800 R) C57BL/6 mice reconstituted with B10 X Thy-1.1 bone marrow cells by assaying in part-body-shielded and irradiated C57BL/6 mice, the activity of these two organs showed quite a different time course of development. The results strongly suggest that the stem cells for T cell lineage in the bone marrow comprise at least two subpopulations, spleen-seeking and bone marrow-seeking cells

Cyanobacterial Biofuels: Strategies and Developments on Network and Modeling.

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Klanchui, Amornpan; Raethong, Nachon; Prommeenate, Peerada; Vongsangnak, Wanwipa; Meechai, Asawin

Cyanobacteria, the phototrophic microorganisms, have attracted much attention recently as a promising source for environmentally sustainable biofuels production. However, barriers for commercial markets of cyanobacteria-based biofuels concern the economic feasibility. Miscellaneous strategies for improving the production performance of cyanobacteria have thus been developed. Among these, the simple ad hoc strategies resulting in failure to optimize fully cell growth coupled with desired product yield are explored. With the advancement of genomics and systems biology, a new paradigm toward systems metabolic engineering has been recognized. In particular, a genome-scale metabolic network reconstruction and modeling is a crucial systems-based tool for whole-cell-wide investigation and prediction. In this review, the cyanobacterial genome-scale metabolic models, which offer a system-level understanding of cyanobacterial metabolism, are described. The main process of metabolic network reconstruction and modeling of cyanobacteria are summarized. Strategies and developments on genome-scale network and modeling through the systems metabolic engineering approach are advanced and employed for efficient cyanobacterial-based biofuels production.

Polycomb enables primitive endoderm lineage priming in embryonic stem cells

DEFF Research Database (Denmark)

Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V

2016-01-01

Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver...... polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision....

Determining the control networks regulating stem cell lineages in colonic crypts

OpenAIRE

Yang, J; Axelrod, DE; Komarova, NL

2017-01-01

The question of stem cell control is at the center of our understanding of tissue functioning, both in healthy and cancerous conditions. It is well accepted that cellular fate decisions (such as divisions, differentiation, apoptosis) are orchestrated by a network of regulatory signals emitted by different cell populations in the lineage and the surrounding tissue. The exact regulatory network that governs stem cell lineages in a given tissue is usually unknown. Here we propose an algorithm to...

Aerobic lineage of the oxidative stress response protein rubrerythrin emerged in an ancient microaerobic, (hyperthermophilic environment

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Juan Pablo Cardenas

2016-11-01

Full Text Available Rubrerythrins (RBRs are non-heme di-iron proteins belonging to the ferritin-like superfamily (FLSF. They are involved in oxidative stress defense as peroxide scavengers in a wide range of organisms. The vast majority of RBRs, including classical forms of this protein, contain a C-terminal rubredoxin-like domain involved in electron transport that is used during catalysis in anaerobic conditions. Rubredoxin is an ancient and large protein family of short length (<100 residues that contains a Fe-S center involved in electron transfer. However, functional forms of the enzyme lacking the rubredoxin-like domain have been reported (e.g., sulerythrin and ferriperoxin. In this study, phylogenomic evidence is presented that suggests that a complete lineage of rubrerythrins, lacking the rubredoxin-like domain, arose in an ancient microaerobic and (hyperthermophilic environments in the ancestors of the Archaea Thermoproteales and Sulfolobales. This lineage (termed the aerobic-type lineage subsequently evolved to become adapted to environments with progressively lower temperatures and higher oxygen concentrations via the acquisition of two co-localized genes, termed DUF3501 and RFO, encoding a conserved protein of unknown function and a predicted Fe-S oxidoreductase respectively. Proposed Horizontal Gene Transfer (HGT events from these archaeal ancestors to Bacteria expanded the opportunities for further evolution of this RBR including adaption to lower temperatures. The second lineage (termed the cyanobacterial lineage is proposed to have evolved in cyanobacterial ancestors, maybe in direct response to the production of oxygen via oxygenic photosynthesis during the Great Oxygen Event (GOE. It is hypothesized that both lineages of RBR emerged in a largely anaerobic world with whiffs of oxygen and that their subsequent independent evolutionary trajectories allowed microorganisms to transition from this anaerobic world to an aerobic one.

Effect of ozonation on the removal of cyanobacterial toxins during drinking water treatment.

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Hoeger, Stefan J; Dietrich, Daniel R; Hitzfeld, Bettina C

2002-01-01

Water treatment plants faced with toxic cyanobacteria have to be able to remove cyanotoxins from raw water. In this study we investigated the efficacy of ozonation coupled with various filtration steps under different cyanobacterial bloom conditions. Cyanobacteria were ozonated in a laboratory-scale batch reactor modeled on a system used by a modern waterworks, with subsequent activated carbon and sand filtration steps. The presence of cyanobacterial toxins (microcystins) was determined using the protein phosphatase inhibition assay. We found that ozone concentrations of at least 1.5 mg/L were required to provide enough oxidation potential to destroy the toxin present in 5 X 10(5 )Microcystis aeruginosa cells/mL [total organic carbon (TOC), 1.56 mg/L]. High raw water TOC was shown to reduce the efficiency of free toxin oxidation and destruction. In addition, ozonation of raw waters containing high cyanobacteria cell densities will result in cell lysis and liberation of intracellular toxins. Thus, we emphasize that only regular and simultaneous monitoring of TOC/dissolved organic carbon and cyanobacterial cell densities, in conjunction with online residual O(3) concentration determination and efficient filtration steps, can ensure the provision of safe drinking water from surface waters contaminated with toxic cyanobacterial blooms. PMID:12417484

Long-term live cell imaging and automated 4D analysis of drosophila neuroblast lineages.

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Catarina C F Homem

Full Text Available The developing Drosophila brain is a well-studied model system for neurogenesis and stem cell biology. In the Drosophila central brain, around 200 neural stem cells called neuroblasts undergo repeated rounds of asymmetric cell division. These divisions typically generate a larger self-renewing neuroblast and a smaller ganglion mother cell that undergoes one terminal division to create two differentiating neurons. Although single mitotic divisions of neuroblasts can easily be imaged in real time, the lack of long term imaging procedures has limited the use of neuroblast live imaging for lineage analysis. Here we describe a method that allows live imaging of cultured Drosophila neuroblasts over multiple cell cycles for up to 24 hours. We describe a 4D image analysis protocol that can be used to extract cell cycle times and growth rates from the resulting movies in an automated manner. We use it to perform lineage analysis in type II neuroblasts where clonal analysis has indicated the presence of a transit-amplifying population that potentiates the number of neurons. Indeed, our experiments verify type II lineages and provide quantitative parameters for all cell types in those lineages. As defects in type II neuroblast lineages can result in brain tumor formation, our lineage analysis method will allow more detailed and quantitative analysis of tumorigenesis and asymmetric cell division in the Drosophila brain.

Molecular Diffusion through Cyanobacterial Septal Junctions.

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Nieves-Morión, Mercedes; Mullineaux, Conrad W; Flores, Enrique

2017-01-03

Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N 2 -fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO 2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP) assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the "septal junctions" (formerly known as "microplasmodesmata") linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans. Although bacteria are frequently considered just as unicellular organisms, there are bacteria that behave as true multicellular organisms. The heterocyst-forming cyanobacteria grow as filaments in which cells communicate. Intercellular molecular exchange is thought to be mediated by septal junctions. Here, we show that intercellular transfer of fluorescent markers in the cyanobacterial filament has the physical properties of simple diffusion. Thus, cyanobacterial septal junctions are functionally analogous to metazoan gap junctions

Cyanobacterial Oxygenic Photosynthesis is Protected by Flavodiiron Proteins

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Yagut Allahverdiyeva

2015-03-01

Full Text Available Flavodiiron proteins (FDPs, also called flavoproteins, Flvs are modular enzymes widely present in Bacteria and Archaea. The evolution of cyanobacteria and oxygenic photosynthesis occurred in concert with the modulation of typical bacterial FDPs. Present cyanobacterial FDPs are composed of three domains, the β-lactamase-like, flavodoxin-like and flavin-reductase like domains. Cyanobacterial FDPs function as hetero- and homodimers and are involved in the regulation of photosynthetic electron transport. Whilst Flv2 and Flv4 proteins are limited to specific cyanobacterial species (β-cyanobacteria and function in photoprotection of Photosystem II, Flv1 and Flv3 proteins, functioning in the “Mehler-like” reaction and safeguarding Photosystem I under fluctuating light conditions, occur in nearly all cyanobacteria and additionally in green algae, mosses and lycophytes. Filamentous cyanobacteria have additional FDPs in heterocyst cells, ensuring a microaerobic environment for the function of the nitrogenase enzyme under the light. Here, the evolution, occurrence and functional mechanisms of various FDPs in oxygenic photosynthetic organisms are discussed.

Mesenchymal progenitor cells for the osteogenic lineage.

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Ono, Noriaki; Kronenberg, Henry M

2015-09-01

Mesenchymal progenitors of the osteogenic lineage provide the flexibility for bone to grow, maintain its function and homeostasis. Traditionally, colony-forming-unit fibroblasts (CFU-Fs) have been regarded as surrogates for mesenchymal progenitors; however, this definition cannot address the function of these progenitors in their native setting. Transgenic murine models including lineage-tracing technologies based on the cre-lox system have proven to be useful in delineating mesenchymal progenitors in their native environment. Although heterogeneity of cell populations of interest marked by a promoter-based approach complicates overall interpretation, an emerging complexity of mesenchymal progenitors has been revealed. Current literatures suggest two distinct types of bone progenitor cells; growth-associated mesenchymal progenitors contribute to explosive growth of bone in early life, whereas bone marrow mesenchymal progenitors contribute to the much slower remodeling process and response to injury that occurs mainly in adulthood. More detailed relationships of these progenitors need to be studied through further experimentation.

Retinoic Acid Is Essential for Th1 Cell Lineage Stability and Prevents Transition to a Th17 Cell Program

Science.gov (United States)

Brown, Chrysothemis C.; Esterhazy, Daria; Sarde, Aurelien; London, Mariya; Pullabhatla, Venu; Osma-Garcia, Ines; al-Bader, Raya; Ortiz, Carla; Elgueta, Raul; Arno, Matthew; de Rinaldis, Emanuele; Mucida, Daniel; Lord, Graham M.; Noelle, Randolph J.

2015-01-01

Summary CD4+ T cells differentiate into phenotypically distinct T helper cells upon antigenic stimulation. Regulation of plasticity between these CD4+ T-cell lineages is critical for immune homeostasis and prevention of autoimmune disease. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARα, sustains stable expression of Th1 lineage specifying genes, as well as repressing genes that instruct Th17-cell fate. RA signaling is essential for limiting Th1-cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our study identifies RA-RARα as a key component of the regulatory network governing maintenance and plasticity of Th1-cell fate and defines an additional pathway for the development of Th17 cells. PMID:25769610

Clonal analysis of the cell lineages in the male flower of maize

International Nuclear Information System (INIS)

Dawe, R.K.; Freeling, M.

1990-01-01

The cell lineages in the male flower of maize were characterized using X-rays and transposable elements to produce clonal sectors differing in anthocyanin pigmentation. Less than 50% of the somatic tassel mutations (caused by reversion of unstable color mutations) that were visible on the anther wall were sexually transmitted by the male gametes, unless the sectors were larger than half the tassel circumference. This result is explained by showing that: (a) both the outer (LI) and inner (LII) lineages of the shoot apical meristem form a cell layer in the bilayered anther wall, and that anther pigmentation can be derived from either cell layer; and that (b) the male germ cells are derived almost exclusively from the LII. Therefore, while reversion events in either the LI or LII are visible on the anther, only the LII events are heritable. Reversion events that occur prior to the organization of the shoot apical meristem however, produce large (usually more than one-half tassel) sectors that include both the outer and inner lineages. In contrast to the high level of cell layer invasion previously reported during leaf development, during anther development less than 10(-3) cells in the LI invade the LII to form male gametes. The strong correlation between cell lineage and cell fate in the maize anther has implications for studies on plant evolution and the genetic improvement of cereals by DNA transformation

Differentiation of Equine Mesenchymal Stromal Cells into Cells of Neural Lineage: Potential for Clinical Applications

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Claudia Cruz Villagrán

2014-01-01

Full Text Available Mesenchymal stromal cells (MSCs are able to differentiate into extramesodermal lineages, including neurons. Positive outcomes were obtained after transplantation of neurally induced MSCs in laboratory animals after nerve injury, but this is unknown in horses. Our objectives were to test the ability of equine MSCs to differentiate into cells of neural lineage in vitro, to assess differences in morphology and lineage-specific protein expression, and to investigate if horse age and cell passage number affected the ability to achieve differentiation. Bone marrow-derived MSCs were obtained from young and adult horses. Following demonstration of stemness, MSCs were neurally induced and microscopically assessed at different time points. Results showed that commercially available nitrogen-coated tissue culture plates supported proliferation and differentiation. Morphological changes were immediate and all the cells displayed a neural crest-like cell phenotype. Expression of neural progenitor proteins, was assessed via western blot or immunofluorescence. In our study, MSCs generated from young and middle-aged horses did not show differences in their ability to undergo differentiation. The effect of cell passage number, however, is inconsistent and further experiments are needed. Ongoing work is aimed at transdifferentiating these cells into Schwann cells for transplantation into a peripheral nerve injury model in horses.

Retinoic acid is essential for Th1 cell lineage stability and prevents transition to a Th17 cell program.

Science.gov (United States)

Brown, Chrysothemis C; Esterhazy, Daria; Sarde, Aurelien; London, Mariya; Pullabhatla, Venu; Osma-Garcia, Ines; Al-Bader, Raya; Ortiz, Carla; Elgueta, Raul; Arno, Matthew; de Rinaldis, Emanuele; Mucida, Daniel; Lord, Graham M; Noelle, Randolph J

2015-03-17

CD4(+) T cells differentiate into phenotypically distinct T helper cells upon antigenic stimulation. Regulation of plasticity between these CD4(+) T-cell lineages is critical for immune homeostasis and prevention of autoimmune disease. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARα, sustains stable expression of Th1 lineage specifying genes, as well as repressing genes that instruct Th17-cell fate. RA signaling is essential for limiting Th1-cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our study identifies RA-RARα as a key component of the regulatory network governing maintenance and plasticity of Th1-cell fate and defines an additional pathway for the development of Th17 cells. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Genotoxicity and potential carcinogenicity of cyanobacterial toxins - a review.

Science.gov (United States)

Zegura, Bojana; Straser, Alja; Filipič, Metka

2011-01-01

The occurrence of cyanobacterial blooms has increased significantly in many regions of the world in the last century due to water eutrophication. These blooms are hazardous to humans, animals, and plants due to the production of cyanotoxins, which can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). There is evidence that certain cyanobacterial toxins are genotoxic and carcinogenic; however, the mechanisms of their potential carcinogenicity are not well understood. The most frequently occurring and widespread cyanotoxins in brackish and freshwater blooms are the cyclic heptapeptides, i.e., microcystins (MCs), and the pentapeptides, i.e., nodularins (NODs). The main mechanism associated with potential carcinogenic activity of MCs and NOD is the inhibition of protein phosphatases, which leads to the hyperphosphorylation of cellular proteins, which is considered to be associated with their tumor-promoting activity. Apart from this, MCs and NOD induce increased formation of reactive oxygen species and, consequently, oxidative DNA damage. There is also evidence that MCs and NOD induce micronuclei, and NOD was shown to have aneugenic activity. Both cyanotoxins interfere with DNA damage repair pathways, which, along with DNA damage, is an important factor involved in the carcinogenicity of these agents. Furthermore, these toxins increase the expression of TNF-α and early-response genes, including proto-oncogenes, genes involved in the response to DNA damage, cell cycle arrest, and apoptosis. Rodent studies indicate that MCs and NOD are tumor promotors, whereas NOD is thought to have also tumor-initiating activity. Another cyanobacterial toxin, cylindrospermopsin (CYN), which has been neglected for a long time, is lately being increasingly found in the freshwater environment. The principal mechanism of its toxicity is the irreversible inhibition of protein synthesis. It is pro

Single-cell protein secretomic signatures as potential correlates to tumor cell lineage evolution and cell-cell interaction

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Minsuk eKwak

2013-02-01

Full Text Available Secreted proteins including cytokines, chemokines and growth factors represent important functional regulators mediating a range of cellular behavior and cell-cell paracrine/autocrine signaling, e.g. in the immunological system, tumor microenvironment or stem cell niche. Detection of these proteins is of great value not only in basic cell biology but also for diagnosis and therapeutic monitoring of human diseases such as cancer. However, due to co-production of multiple effector proteins from a single cell, referred to as polyfunctionality, it is biologically informative to measure a panel of secreted proteins, or secretomic signature, at the level of single cells. Recent evidence further indicates that a genetically-identical cell population can give rise to diverse phenotypic differences. It is known that cytokines, for example, in the immune system define the effector functions and lineage differentiation of immune cells. In this Perspective Article, we hypothesize that protein secretion profile may represent a universal measure to identify the definitive correlate in the larger context of cellular functions to dissect cellular heterogeneity and evolutionary lineage relationship in human cancer.

Telomerase Protects Werner Syndrome Lineage-Specific Stem Cells from Premature Aging

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Hoi-Hung Cheung

2014-04-01

Full Text Available Werner syndrome (WS patients exhibit premature aging predominantly in mesenchyme-derived tissues, but not in neural lineages, a consequence of telomere dysfunction and accelerated senescence. The cause of this lineage-specific aging remains unknown. Here, we document that reprogramming of WS fibroblasts to pluripotency elongated telomere length and prevented telomere dysfunction. To obtain mechanistic insight into the origin of tissue-specific aging, we differentiated iPSCs to mesenchymal stem cells (MSCs and neural stem/progenitor cells (NPCs. We observed recurrence of premature senescence associated with accelerated telomere attrition and defective synthesis of the lagging strand telomeres in MSCs, but not in NPCs. We postulate this “aging” discrepancy is regulated by telomerase. Expression of hTERT or p53 knockdown ameliorated the accelerated aging phenotypein MSC, whereas inhibition of telomerase sensitized NPCs to DNA damage. Our findings unveil a role for telomerase in the protection of accelerated aging in a specific lineage of stem cells.

The cyanobacterial metabolite nocuolin a is a natural oxadiazine that triggers apoptosis in human cancer cells.

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Kateřina Voráčová

Full Text Available Oxadiazines are heterocyclic compounds containing N-N-O or N-N-C-O system within a six membered ring. These structures have been up to now exclusively prepared via organic synthesis. Here, we report the discovery of a natural oxadiazine nocuolin A (NoA that has a unique structure based on 1,2,3-oxadiazine. We have identified this compound in three independent cyanobacterial strains of genera Nostoc, Nodularia, and Anabaena and recognized the putative gene clusters for NoA biosynthesis in their genomes. Its structure was characterized using a combination of NMR, HRMS and FTIR methods. The compound was first isolated as a positive hit during screening for apoptotic inducers in crude cyanobacterial extracts. We demonstrated that NoA-induced cell death has attributes of caspase-dependent apoptosis. Moreover, NoA exhibits a potent anti-proliferative activity (0.7-4.5 μM against several human cancer lines, with p53-mutated cell lines being even more sensitive. Since cancers bearing p53 mutations are resistant to several conventional anti-cancer drugs, NoA may offer a new scaffold for the development of drugs that have the potential to target tumor cells independent of their p53 status. As no analogous type of compound was previously described in the nature, NoA establishes a novel class of bioactive secondary metabolites.

Cell fate determination in the Caenorhabditis elegans epidermal lineages

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Soete, G.A.J.

2007-01-01

The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly

Lineage specific expression of Polycomb Group Proteins in human embryonic stem cells in vitro.

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Pethe, Prasad; Pursani, Varsha; Bhartiya, Deepa

2015-05-01

Human embryonic (hES) stem cells are an excellent model to study lineage specification and differentiation into various cell types. Differentiation necessitates repression of specific genes not required for a particular lineage. Polycomb Group (PcG) proteins are key histone modifiers, whose primary function is gene repression. PcG proteins form complexes called Polycomb Repressive Complexes (PRCs), which catalyze histone modifications such as H2AK119ub1, H3K27me3, and H3K9me3. PcG proteins play a crucial role during differentiation of stem cells. The expression of PcG transcripts during differentiation of hES cells into endoderm, mesoderm, and ectoderm lineage is yet to be shown. In-house derived hES cell line KIND1 was differentiated into endoderm, mesoderm, and ectoderm lineages; followed by characterization using RT-PCR for HNF4A, CDX2, MEF2C, TBX5, SOX1, and MAP2. qRT-PCR and western blotting was performed to compare expression of PcG transcripts and proteins across all the three lineages. We observed that cells differentiated into endoderm showed upregulation of RING1B, BMI1, EZH2, and EED transcripts. Mesoderm differentiation was characterized by significant downregulation of all PcG transcripts during later stages. BMI1 and RING1B were upregulated while EZH2, SUZ12, and EED remained low during ectoderm differentiation. Western blotting also showed distinct expression of BMI1 and EZH2 during differentiation into three germ layers. Our study shows that hES cells differentiating into endoderm, mesoderm, and ectoderm lineages show distinct PcG expression profile at transcript and protein level. © 2015 International Federation for Cell Biology.

Pox neuro control of cell lineages that give rise to larval poly-innervated external sensory organs in Drosophila.

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Jiang, Yanrui; Boll, Werner; Noll, Markus

2015-01-15

The Pox neuro (Poxn) gene of Drosophila plays a crucial role in the development of poly-innervated external sensory (p-es) organs. However, how Poxn exerts this role has remained elusive. In this study, we have analyzed the cell lineages of all larval p-es organs, namely of the kölbchen, papilla 6, and hair 3. Surprisingly, these lineages are distinct from any previously reported cell lineages of sensory organs. Unlike the well-established lineage of mono-innervated external sensory (m-es) organs and a previously proposed model of the p-es lineage, we demonstrate that all wild-type p-es lineages exhibit the following features: the secondary precursor, pIIa, gives rise to all three support cells-socket, shaft, and sheath, whereas the other secondary precursor, pIIb, is neuronal and gives rise to all neurons. We further show that in one of the p-es lineages, that of papilla 6, one cell undergoes apoptosis. By contrast in Poxn null mutants, all p-es lineages have a reduced number of cells and their pattern of cell divisions is changed to that of an m-es organ, with the exception of a lineage in a minority of mutant kölbchen that retains a second bipolar neuron. Indeed, the role of Poxn in p-es lineages is consistent with the specification of the developmental potential of secondary precursors and the regulation of cell division but not apoptosis. Copyright © 2014 Elsevier Inc. All rights reserved.

Analysis of Microcystins in Cyanobacterial Blooms from Freshwater Bodies in England

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Andrew D. Turner

2018-01-01

Full Text Available Cyanobacterial blooms in freshwater bodies in England are currently monitored reactively, with samples containing more than 20,000 cells/mL of potentially toxin-producing species by light microscopy resulting in action by the water body owner. Whilst significantly reducing the risk of microcystin exposure, there is little data describing the levels of these toxins present in cyanobacterial blooms. This study focused on the quantitative LC-MS/MS analysis of microcystins in freshwater samples, collected across England during 2016 and found to contain potentially toxin-producing cyanobacteria. More than 50% of samples contained quantifiable concentrations of microcystins, with approximately 13% exceeding the WHO medium health threshold of 20 μg/L. Toxic samples were confirmed over a nine-month period, with a clear increase in toxins during late summer, but with no apparent geographical patterns. No statistical relationships were found between total toxin concentrations and environmental parameters. Complex toxin profiles were determined and profile clusters were unrelated to cyanobacterial species, although a dominance of MC-RR was determined in water samples from sites associated with lower rainfall. 100% of samples with toxins above the 20 μg/L limit contained cell densities above 20,000 cells/mL or cyanobacterial scum, showing the current regime is suitable for public health. Conversely, with only 18% of cell density threshold samples having total microcystins above 20 μg/L, there is the potential for reactive water closures to unnecessarily impact upon the socio-economics of the local population. In the future, routine analysis of bloom samples by LC-MS/MS would provide a beneficial confirmatory approach to the current microscopic assessment, aiding both public health and the needs of water users and industry.

Single-cell transcriptomic reconstruction reveals cell cycle and multi-lineage differentiation defects in Bcl11a-deficient hematopoietic stem cells.

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Tsang, Jason C H; Yu, Yong; Burke, Shannon; Buettner, Florian; Wang, Cui; Kolodziejczyk, Aleksandra A; Teichmann, Sarah A; Lu, Liming; Liu, Pentao

2015-09-21

Hematopoietic stem cells (HSCs) are a rare cell type with the ability of long-term self-renewal and multipotency to reconstitute all blood lineages. HSCs are typically purified from the bone marrow using cell surface markers. Recent studies have identified significant cellular heterogeneities in the HSC compartment with subsets of HSCs displaying lineage bias. We previously discovered that the transcription factor Bcl11a has critical functions in the lymphoid development of the HSC compartment. In this report, we employ single-cell transcriptomic analysis to dissect the molecular heterogeneities in HSCs. We profile the transcriptomes of 180 highly purified HSCs (Bcl11a (+/+) and Bcl11a (-/-)). Detailed analysis of the RNA-seq data identifies cell cycle activity as the major source of transcriptomic variation in the HSC compartment, which allows reconstruction of HSC cell cycle progression in silico. Single-cell RNA-seq profiling of Bcl11a (-/-) HSCs reveals abnormal proliferative phenotypes. Analysis of lineage gene expression suggests that the Bcl11a (-/-) HSCs are constituted of two distinct myeloerythroid-restricted subpopulations. Remarkably, similar myeloid-restricted cells could also be detected in the wild-type HSC compartment, suggesting selective elimination of lymphoid-competent HSCs after Bcl11a deletion. These defects are experimentally validated in serial transplantation experiments where Bcl11a (-/-) HSCs are myeloerythroid-restricted and defective in self-renewal. Our study demonstrates the power of single-cell transcriptomics in dissecting cellular process and lineage heterogeneities in stem cell compartments, and further reveals the molecular and cellular defects in the Bcl11a-deficient HSC compartment.

Effect of Environmental Factors on Cyanobacterial Abundance and Cyanotoxins Production in Natural and Drinking Water, Bangladesh.

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Affan, Abu; Khomavis, Hisham S; Al-Harbi, Salim Marzoog; Haque, Mahfuzul; Khan, Saleha

2015-02-01

Cyanobacterial blooms commonly appear during the summer months in ponds, lakes and reservoirs in Bangladesh. In these areas, fish mortality, odorous water and fish and human skin irritation and eye inflammation have been reported. The influence of physicochemical factors on the occurrence of cyanobacteria and its toxin levels were evaluated in natural and drinking water in Bangladesh. A highly sensitive immunosorbent assay was used to detect microcystins (MCs). Cyanobacteria were found in 22 of 23 samples and the dominant species were Microcystis aeruginosa, followed by Microcystisflosaquae, Anabeana crassa and Aphanizomenon flosaquae. Cyanobacterial abundance varied from 39 to 1315 x 10(3) cells mL(-1) in natural water and 31 to 49 x 10(3) cells mL(-1) in tap water. MC concentrations were 25-82300 pg mL(-1) with the highest value measured in the fish research pond, followed by Ishakha Lake. In tap water, MC concentrations ranged from 30-32 pg mL(-1). The correlation between nitrate-nitrogen (NO3-N) concentration and cyanobacterial cell abundance was R2 = 0.62 while that between cyanobacterial abundance and MC concentration was R2 = 0.98. The increased NO3-N from fish feed, organic manure, poultry and dairy farm waste and fertilizer from agricultural land eutrophicated the water bodies and triggered cyanobacterial bloom formation. The increased amount of cyanobacteria produced MCs, subsequently reducing the water quality.

Hacking cell differentiation: transcriptional rerouting in reprogramming, lineage infidelity and metaplasia.

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Regalo, Gonçalo; Leutz, Achim

2013-08-01

Initiating neoplastic cell transformation events are of paramount importance for the comprehension of regeneration and vanguard oncogenic processes but are difficult to characterize and frequently clinically overlooked. In epithelia, pre-neoplastic transformation stages are often distinguished by the appearance of phenotypic features of another differentiated tissue, termed metaplasia. In haemato/lymphopoietic malignancies, cell lineage ambiguity is increasingly recorded. Both, metaplasia and biphenotypic leukaemia/lymphoma represent examples of dysregulated cell differentiation that reflect a history of trans-differentiation and/or epigenetic reprogramming. Here we compare the similarity between molecular events of experimental cell trans-differentiation as an emerging therapeutic concept, with lineage confusion, as in metaplasia and dysplasia forecasting tumour development. © 2013 The Authors. Published by John Wiley and Sons, Ltd on behalf of EMBO.

Eutrophication and warming boost cyanobacterial biomass and microcystins

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Lurling, Miguel; Oosterhout, Jean; Faassen, Els

2017-01-01

Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC) concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial

Multiple mesodermal lineage differentiation of Apodemus sylvaticus embryonic stem cells in vitro

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Yu Weihua

2010-06-01

Full Text Available Abstract Background Embryonic stem (ES cells have attracted significant attention from researchers around the world because of their ability to undergo indefinite self-renewal and produce derivatives from the three cell lineages, which has enormous value in research and clinical applications. Until now, many ES cell lines of different mammals have been established and studied. In addition, recently, AS-ES1 cells derived from Apodemus sylvaticus were established and identified by our laboratory as a new mammalian ES cell line. Hence further research, in the application of AS-ES1 cells, is warranted. Results Herein we report the generation of multiple mesodermal AS-ES1 lineages via embryoid body (EB formation by the hanging drop method and the addition of particular reagents and factors for induction at the stage of EB attachment. The AS-ES1 cells generated separately in vitro included: adipocytes, osteoblasts, chondrocytes and cardiomyocytes. Histochemical staining, immunofluorescent staining and RT-PCR were carried out to confirm the formation of multiple mesodermal lineage cells. Conclusions The appropriate reagents and culture milieu used in mesodermal differentiation of mouse ES cells also guide the differentiation of in vitro AS-ES1 cells into distinct mesoderm-derived cells. This study provides a better understanding of the characteristics of AS-ES1 cells, a new species ES cell line and promotes the use of Apodemus ES cells as a complement to mouse ES cells in future studies.

Dynamics of lineage commitment revealed by single-cell transcriptomics of differentiating embryonic stem cells

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Semrau, Stefan; Goldmann, Johanna E; Soumillon, Magali; Mikkelsen, Tarjei S; Jaenisch, Rudolf; van Oudenaarden, Alexander

2017-01-01

Gene expression heterogeneity in the pluripotent state of mouse embryonic stem cells (mESCs) has been increasingly well-characterized. In contrast, exit from pluripotency and lineage commitment have not been studied systematically at the single-cell level. Here we measure the gene expression

Cell tracing reveals a dorsoventral lineage restriction plane in the mouse limb bud mesenchyme.

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Arques, Carlos G; Doohan, Roisin; Sharpe, James; Torres, Miguel

2007-10-01

Regionalization of embryonic fields into independent units of growth and patterning is a widespread strategy during metazoan development. Compartments represent a particular instance of this regionalization, in which unit coherence is maintained by cell lineage restriction between adjacent regions. Lineage compartments have been described during insect and vertebrate development. Two common characteristics of the compartments described so far are their occurrence in epithelial structures and the presence of signaling regions at compartment borders. Whereas Drosophila compartmental organization represents a background subdivision of embryonic fields that is not necessarily related to anatomical structures, vertebrate compartment borders described thus far coincide with, or anticipate, anatomical or cell-type discontinuities. Here, we describe a general method for clonal analysis in the mouse and use it to determine the topology of clone distribution along the three limb axes. We identify a lineage restriction boundary at the limb mesenchyme dorsoventral border that is unrelated to any anatomical discontinuity, and whose lineage restriction border is not obviously associated with any signaling center. This restriction is the first example in vertebrates of a mechanism of primordium subdivision unrelated to anatomical boundaries. Furthermore, this is the first lineage compartment described within a mesenchymal structure in any organism, suggesting that lineage restrictions are fundamental not only for epithelial structures, but also for mesenchymal field patterning. No lineage compartmentalization was found along the proximodistal or anteroposterior axes, indicating that patterning along these axes does not involve restriction of cell dispersion at specific axial positions.

The differentiation potential of adipose tissue-derived mesenchymal stem cells into cell lineage related to male germ cells

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P. Bräunig

Full Text Available ABSTRACT The adipose tissue is a reliable source of Mesenchymal stem cells (MSCs showing a higher plasticity and transdifferentiation potential into multilineage cells. In the present study, adipose tissue-derived mesenchymal stem cells (AT-MSCs were isolated from mice omentum and epididymis fat depots. The AT-MSCs were initially compared based on stem cell surface markers and on the mesodermal trilineage differentiation potential. Additionally, AT-MSCs, from both sources, were cultured with differentiation media containing retinoic acid (RA and/or testicular cell-conditioned medium (TCC. The AT-MSCs expressed mesenchymal surface markers and differentiated into adipogenic, chondrogenic and osteogenic lineages. Only omentum-derived AT-MSCs expressed one important gene marker related to male germ cell lineages, after the differentiation treatment with RA. These findings reaffirm the importance of adipose tissue as a source of multipotent stromal-stem cells, as well as, MSCs source regarding differentiation purpose.

Integrin αv in the mechanical response of osteoblast lineage cells

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Kaneko, Keiko [Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan); Ito, Masako [Medical Work-Life-Balance Center, Nagasaki University Hospital, Nagasaki 852-8501 (Japan); Naoe, Yoshinori [Department of Mechanism of Aging, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan); Lacy-Hulbert, Adam [Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114 (United States); Ikeda, Kyoji, E-mail: kikeda@ncgg.go.jp [Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan)

2014-05-02

Highlights: • Deletion of integrin αv in osteoblast lineage results in an impaired SOST response to loading in vivo. • c-Src–p130Cas–JNK–YAP/TAZ is activated via integrin αv on osteoblasts in response to FSS. • Deletion of integrin αv in osteoblasts results in impaired responses to mechanical stimulation. • Integrin αv is a key component of the mechanosensing machinery in bone. - Abstract: Although osteoblast lineage cells, especially osteocytes, are thought to be a primary mechanosensory cell in bone, the identity of the mechano-receptor and downstream mechano-signaling pathways remain largely unknown. Here we show using osteoblastic cell model of mechanical stimulation with fluid shear stress that in the absence of integrin αv, phosphorylation of the Src substrate p130Cas and JNK was impaired, culminating in an inhibition of nuclear translocation of YAP/TAZ and subsequent transcriptional activation of target genes. Targeted deletion of the integrin αv in osteoblast lineage cells results in an attenuated response to mechanical loading in terms of Sost gene expression, indicative of a role for integrin αv in mechanoreception in vivo. Thus, integrin αv may be integral to a mechanosensing machinery in osteoblastic cells and involved in activation of a Src–JNK–YAP/TAZ pathway in response to mechanical stimulation.

Integrin αv in the mechanical response of osteoblast lineage cells

International Nuclear Information System (INIS)

Kaneko, Keiko; Ito, Masako; Naoe, Yoshinori; Lacy-Hulbert, Adam; Ikeda, Kyoji

2014-01-01

Highlights: • Deletion of integrin αv in osteoblast lineage results in an impaired SOST response to loading in vivo. • c-Src–p130Cas–JNK–YAP/TAZ is activated via integrin αv on osteoblasts in response to FSS. • Deletion of integrin αv in osteoblasts results in impaired responses to mechanical stimulation. • Integrin αv is a key component of the mechanosensing machinery in bone. - Abstract: Although osteoblast lineage cells, especially osteocytes, are thought to be a primary mechanosensory cell in bone, the identity of the mechano-receptor and downstream mechano-signaling pathways remain largely unknown. Here we show using osteoblastic cell model of mechanical stimulation with fluid shear stress that in the absence of integrin αv, phosphorylation of the Src substrate p130Cas and JNK was impaired, culminating in an inhibition of nuclear translocation of YAP/TAZ and subsequent transcriptional activation of target genes. Targeted deletion of the integrin αv in osteoblast lineage cells results in an attenuated response to mechanical loading in terms of Sost gene expression, indicative of a role for integrin αv in mechanoreception in vivo. Thus, integrin αv may be integral to a mechanosensing machinery in osteoblastic cells and involved in activation of a Src–JNK–YAP/TAZ pathway in response to mechanical stimulation

Distinct epigenomic landscapes of pluripotent and lineage-committed human cells.

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Hawkins, R David; Hon, Gary C; Lee, Leonard K; Ngo, Queminh; Lister, Ryan; Pelizzola, Mattia; Edsall, Lee E; Kuan, Samantha; Luu, Ying; Klugman, Sarit; Antosiewicz-Bourget, Jessica; Ye, Zhen; Espinoza, Celso; Agarwahl, Saurabh; Shen, Li; Ruotti, Victor; Wang, Wei; Stewart, Ron; Thomson, James A; Ecker, Joseph R; Ren, Bing

2010-05-07

Human embryonic stem cells (hESCs) share an identical genome with lineage-committed cells, yet possess the remarkable properties of self-renewal and pluripotency. The diverse cellular properties in different cells have been attributed to their distinct epigenomes, but how much epigenomes differ remains unclear. Here, we report that epigenomic landscapes in hESCs and lineage-committed cells are drastically different. By comparing the chromatin-modification profiles and DNA methylomes in hESCs and primary fibroblasts, we find that nearly one-third of the genome differs in chromatin structure. Most changes arise from dramatic redistributions of repressive H3K9me3 and H3K27me3 marks, which form blocks that significantly expand in fibroblasts. A large number of potential regulatory sequences also exhibit a high degree of dynamics in chromatin modifications and DNA methylation. Additionally, we observe novel, context-dependent relationships between DNA methylation and chromatin modifications. Our results provide new insights into epigenetic mechanisms underlying properties of pluripotency and cell fate commitment.

Cyanobacterial flora from polluted industrial effluents.

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Parikh, Amit; Shah, Vishal; Madamwar, Datta

2006-05-01

Effluents originating from pesticides, agro-chemicals, textile dyes and dyestuffs industries are always associated with high turbidity, colour, nutrient load, and heavy metals, toxic and persistent compounds. But even with such an anthropogenic nature, these effluents contain dynamic cyanobacterial communities. Documentation of cyanobacterial cultures along the water channels of effluents discharged by above mentioned industries along the west coast of India and their relationship with water quality is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of solids, carbon and nutrients were found to be persistent throughout the analysis. Sediment and water samples were found to be colored in nature. Cyanobacterial community structure was found to be influenced by the anthropogenic pollution. 40 different cyanobacterial species were recorded from 14 genera of 5 families and an elevated occurrence of Phormidium, Oscillatoria and Chroococcus genera was observed in all the sampling sites.

Foetal stem cell derivation & characterization for osteogenic lineage

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A Mangala Gowri

2013-01-01

Full Text Available Background & objectives: Mesencymal stem cells (MSCs derived from foetal tissues present a multipotent progenitor cell source for application in tissue engineering and regenerative medicine. The present study was carried out to derive foetal mesenchymal stem cells from ovine source and analyze their differentiation to osteogenic linage to serve as an animal model to predict human applications. Methods: Isolation and culture of sheep foetal bone marrow cells were done and uniform clonally derived MSC population was collected. The cells were characterized using cytochemical, immunophenotyping, biochemical and molecular analyses. The cells with defined characteristics were differentiated into osteogenic lineages and analysis for differentiated cell types was done. The cells were analyzed for cell surface marker expression and the gene expression in undifferentiated and differentiated osteoblast was checked by reverse transcriptase PCR (RT PCR analysis and confirmed by sequencing using genetic analyzer. Results: Ovine foetal samples were processed to obtain mononuclear (MNC cells which on culture showed spindle morphology, a characteristic oval body with the flattened ends. MSC population CD45 - /CD14 - was cultured by limiting dilution to arrive at uniform spindle morphology cells and colony forming units. The cells were shown to be positive for surface markers such as CD44, CD54, integrinβ1, and intracellular collagen type I/III and fibronectin. The osteogenically induced MSCs were analyzed for alkaline phosphatase (ALP activity and mineral deposition. The undifferentiated MSCs expressed RAB3B, candidate marker for stemness in MSCs. The osteogenically induced and uninduced MSCs expressed collagen type I and MMP13 gene in osteogenic induced cells. Interpretation & conclusions: The protocol for isolation of ovine foetal bone marrow derived MSCs was simple to perform, and the cultural method of obtaining pure spindle morphology cells was established

Image segmentation and dynamic lineage analysis in single-cell fluorescence microscopy.

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Wang, Quanli; Niemi, Jarad; Tan, Chee-Meng; You, Lingchong; West, Mike

2010-01-01

An increasingly common component of studies in synthetic and systems biology is analysis of dynamics of gene expression at the single-cell level, a context that is heavily dependent on the use of time-lapse movies. Extracting quantitative data on the single-cell temporal dynamics from such movies remains a major challenge. Here, we describe novel methods for automating key steps in the analysis of single-cell, fluorescent images-segmentation and lineage reconstruction-to recognize and track individual cells over time. The automated analysis iteratively combines a set of extended morphological methods for segmentation, and uses a neighborhood-based scoring method for frame-to-frame lineage linking. Our studies with bacteria, budding yeast and human cells, demonstrate the portability and usability of these methods, whether using phase, bright field or fluorescent images. These examples also demonstrate the utility of our integrated approach in facilitating analyses of engineered and natural cellular networks in diverse settings. The automated methods are implemented in freely available, open-source software.

Differentiation of murine embryonic stem and induced pluripotent stem cells to renal lineage in vitro

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Morizane, Ryuji [Department of Internal Medicine, Keio University School of Medicine, Tokyo (Japan); Monkawa, Toshiaki, E-mail: monkawa@sc.itc.keio.ac.jp [Department of Internal Medicine, Keio University School of Medicine, Tokyo (Japan); Itoh, Hiroshi [Department of Internal Medicine, Keio University School of Medicine, Tokyo (Japan)

2009-12-25

Embryonic stem (ES) cells which have the unlimited proliferative capacity and extensive differentiation potency can be an attractive source for kidney regeneration therapies. Recent breakthroughs in the generation of induced pluripotent stem (iPS) cells have provided with another potential source for the artificially-generated kidney. The purpose of this study is to know how to differentiate mouse ES and iPS cells into renal lineage. We used iPS cells from mouse fibroblasts by transfection of four transcription factors, namely Oct4, Sox2, c-Myc and Klf4. Real-time PCR showed that renal lineage markers were expressed in both ES and iPS cells after the induction of differentiation. It also showed that a tubular specific marker, KSP progressively increased to day 18, although the differentiation of iPS cells was slower than ES cells. The results indicated that renal lineage cells can be differentiated from both murine ES and iPS cells. Several inducing factors were tested whether they influenced on cell differentiation. In ES cells, both of GDNF and BMP7 enhanced the differentiation to metanephric mesenchyme, and Activin enhanced the differentiation of ES cells to tubular cells. Activin also enhanced the differentiation of iPS cells to tubular cells, although the enhancement was lower than in ES cells. ES and iPS cells have a potential to differentiate to renal lineage cells, and they will be an attractive resource of kidney regeneration therapy. This differentiation is enhanced by Activin in both ES and iPS cells.

Carotenoids assist in cyanobacterial Photosystem II assembly and function

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Tomas eZakar

2016-03-01

Full Text Available Carotenoids (carotenes and xanthophylls are ubiquitous constituents of living organisms. They are protective agents against oxidative stresses and serve as modulators of membrane microviscosity. As antioxidants they can protect photosynthetic organisms from free radicals like reactive oxygen species that originate from water splitting, the first step of photosynthesis. We summarize the structural and functional roles of carotenoids in connection with cyanobacterial Photosystem II. Although carotenoids are hydrophobic molecules, their complexes with proteins also allow cytoplasmic localization. In cyanobacterial cells such complexes are called orange carotenoid proteins, and they protect Photosystem II and Photosystem I by preventing their overexcitation through phycobilisomes. Recently it has been observed that carotenoids are not only required for the proper functioning, but also for the structural stability of phycobilisomes.

The differentiation of embryonic stem cells seeded on electrospun nanofibers into neural lineages.

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Xie, Jingwei; Willerth, Stephanie M; Li, Xiaoran; Macewan, Matthew R; Rader, Allison; Sakiyama-Elbert, Shelly E; Xia, Younan

2009-01-01

Due to advances in stem cell biology, embryonic stem (ES) cells can be induced to differentiate into a particular mature cell lineage when cultured as embryoid bodies. Although transplantation of ES cells-derived neural progenitor cells has been demonstrated with some success for either spinal cord injury repair in small animal model, control of ES cell differentiation into complex, viable, higher ordered tissues is still challenging. Mouse ES cells have been induced to become neural progenitors by adding retinoic acid to embryoid body cultures for 4 days. In this study, we examine the use of electrospun biodegradable polymers as scaffolds not only for enhancing the differentiation of mouse ES cells into neural lineages but also for promoting and guiding the neurite outgrowth. A combination of electrospun fiber scaffolds and ES cells-derived neural progenitor cells could lead to the development of a better strategy for nerve injury repair.

Radiation effect on oligodendroglial lineage cells of brain

International Nuclear Information System (INIS)

Yu Dahai; Tianye

2009-01-01

Radiotherapy is a important treatment method for primary and metastatic cancers in the brain. How-ever, a high dose of radiation always leads to the brain injury. A representative pathological manifest of the radiation-induced brain impairment is demyelination. Therefore oligodendrocytes, the myelin-forming cells in the central nervous system, have been focused more attention recently. Oligodendrocytes originate from the migratory, mitotic progenitors and mature progressively into postmitotic myelinating cells. Recent years, a series of studies have been initiated to address the role of oligodendrocyte lineage cells in radiation-induced neurotoxic processes. This article pays attention to these studies, aiming to explore mechanisms of the radiation-induced brain impairment. (authors)

Mouse model of chromosome mosaicism reveals lineage-specific depletion of aneuploid cells and normal developmental potential.

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Bolton, Helen; Graham, Sarah J L; Van der Aa, Niels; Kumar, Parveen; Theunis, Koen; Fernandez Gallardo, Elia; Voet, Thierry; Zernicka-Goetz, Magdalena

2016-03-29

Most human pre-implantation embryos are mosaics of euploid and aneuploid cells. To determine the fate of aneuploid cells and the developmental potential of mosaic embryos, here we generate a mouse model of chromosome mosaicism. By treating embryos with a spindle assembly checkpoint inhibitor during the four- to eight-cell division, we efficiently generate aneuploid cells, resulting in embryo death during peri-implantation development. Live-embryo imaging and single-cell tracking in chimeric embryos, containing aneuploid and euploid cells, reveal that the fate of aneuploid cells depends on lineage: aneuploid cells in the fetal lineage are eliminated by apoptosis, whereas those in the placental lineage show severe proliferative defects. Overall, the proportion of aneuploid cells is progressively depleted from the blastocyst stage onwards. Finally, we show that mosaic embryos have full developmental potential, provided they contain sufficient euploid cells, a finding of significance for the assessment of embryo vitality in the clinic.

Cyanobacterial lipopolysaccharides and human health – a review

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Schluter Philip J

2006-03-01

Full Text Available Abstract Cyanobacterial lipopolysaccharide/s (LPS are frequently cited in the cyanobacteria literature as toxins responsible for a variety of heath effects in humans, from skin rashes to gastrointestinal, respiratory and allergic reactions. The attribution of toxic properties to cyanobacterial LPS dates from the 1970s, when it was thought that lipid A, the toxic moiety of LPS, was structurally and functionally conserved across all Gram-negative bacteria. However, more recent research has shown that this is not the case, and lipid A structures are now known to be very different, expressing properties ranging from LPS agonists, through weak endotoxicity to LPS antagonists. Although cyanobacterial LPS is widely cited as a putative toxin, most of the small number of formal research reports describe cyanobacterial LPS as weakly toxic compared to LPS from the Enterobacteriaceae. We systematically reviewed the literature on cyanobacterial LPS, and also examined the much lager body of literature relating to heterotrophic bacterial LPS and the atypical lipid A structures of some photosynthetic bacteria. While the literature on the biological activity of heterotrophic bacterial LPS is overwhelmingly large and therefore difficult to review for the purposes of exclusion, we were unable to find a convincing body of evidence to suggest that heterotrophic bacterial LPS, in the absence of other virulence factors, is responsible for acute gastrointestinal, dermatological or allergic reactions via natural exposure routes in humans. There is a danger that initial speculation about cyanobacterial LPS may evolve into orthodoxy without basis in research findings. No cyanobacterial lipid A structures have been described and published to date, so a recommendation is made that cyanobacteriologists should not continue to attribute such a diverse range of clinical symptoms to cyanobacterial LPS without research confirmation.

Inductive differentiation of two neural lineages reconstituted in a microculture system from Xenopus early gastrula cells.

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Mitani, S; Okamoto, H

1991-05-01

Neural induction of ectoderm cells has been reconstituted and examined in a microculture system derived from dissociated early gastrula cells of Xenopus laevis. We have used monoclonal antibodies as specific markers to monitor cellular differentiation from three distinct ectoderm lineages in culture (N1 for CNS neurons from neural tube, Me1 for melanophores from neural crest and E3 for skin epidermal cells from epidermal lineages). CNS neurons and melanophores differentiate when deep layer cells of the ventral ectoderm (VE, prospective epidermis region; 150 cells/culture) and an appropriate region of the marginal zone (MZ, prospective mesoderm region; 5-150 cells/culture) are co-cultured, but not in cultures of either cell type on their own; VE cells cultured alone yield epidermal cells as we have previously reported. The extent of inductive neural differentiation in the co-culture system strongly depends on the origin and number of MZ cells initially added to culture wells. The potency to induce CNS neurons is highest for dorsal MZ cells and sharply decreases as more ventrally located cells are used. The same dorsoventral distribution of potency is seen in the ability of MZ cells to inhibit epidermal differentiation. In contrast, the ability of MZ cells to induce melanophores shows the reverse polarity, ventral to dorsal. These data indicate that separate developmental mechanisms are used for the induction of neural tube and neural crest lineages. Co-differentiation of CNS neurons or melanophores with epidermal cells can be obtained in a single well of co-cultures of VE cells (150) and a wide range of numbers of MZ cells (5 to 100). Further, reproducible differentiation of both neural lineages requires intimate association between cells from the two gastrula regions; virtually no differentiation is obtained when cells from the VE and MZ are separated in a culture well. These results indicate that the inducing signals from MZ cells for both neural tube and neural

Proteomic Analysis of Hepatic Tissue of Cyprinus carpio L. Exposed to Cyanobacterial Blooms in Lake Taihu, China

Science.gov (United States)

Jiang, Jinlin; Wang, Xiaorong; Shan, Zhengjun; Yang, Liuyan; Zhou, Junying; Bu, Yuanqin

2014-01-01

With the rapid development of industry and agriculture and associated pollution, the cyanobacterial blooms in Lake Taihu have become a major threat to aquatic wildlife and human health. In this study, the ecotoxicological effects of cyanobacterial blooms on cage-cultured carp (Cyprinus carpio L.) in Meiliang Bay of Lake Taihu were investigated. Microcystins (MCs), major cyanobacterial toxins, have been detected in carp cultured at different experimental sites of Meiliang Bay. We observed that the accumulation of MCs in carp was closely associated with several environmental factors, including temperature, pH value, and density of cyanobacterial blooms. The proteomic profile of carp liver exposed to cyanobacterial blooms was analyzed using two-dimensional difference in-gel electrophoresis (2D-DIGE) and mass spectrometry. The toxic effects of cyanobacterial blooms on carp liver were similar to changes caused by MCs. MCs were transported into liver cells and induced the excessive production of reactive oxygen species (ROS). MCs and ROS inhibited protein phosphatase and aldehyde dehydrogenase (ALDH), directly or indirectly resulting in oxidative stress and disruption of the cytoskeleton. These effects further interfered with metabolic pathways in the liver through the regulation of series of related proteins. The results of this study indicated that cyanobacterial blooms pose a major threat to aquatic wildlife in Meiliang Bay in Lake Taihu. These results provided evidence of the molecular mechanisms underlying liver damage in carp exposed to cyanobacterial blooms. PMID:24558380

Effects of ultrasound on the proliferation and differentiation of cementoblast lineage cells

NARCIS (Netherlands)

Inubushi, T.; Tanaka, E.; Rego, E.B.; Kitagawa, M.; Kawazoe, A.; Ohta, A.; Okada, H.; Koolstra, J.H.; Miyauchi, M.; Takata, T.; Tanne, K.

2008-01-01

Background: The purpose of this study was to investigate the effects of low-intensity pulsed ultrasound (LIPUS) stimulation on the proliferation and differentiation of cementoblast lineage cells. Methods: An immortalized human periodontal ligament cell line (HPL) showing immature cementoblastic

Differentiation in Stem Cell Lineages and in Life: Explorations in the Male Germ Line Stem Cell Lineage.

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Fuller, Margaret T

2016-01-01

I have been privileged to work on cellular differentiation during a great surge of discovery that has revealed the molecular mechanisms and genetic regulatory circuitry that control embryonic development and adult tissue maintenance and repair. Studying the regulation of proliferation and differentiation in the male germ line stem cell lineage has allowed us investigate how the developmental program imposes layers of additional controls on fundamental cellular processes like cell cycle progression and gene expression to give rise to the huge variety of specialized cell types in our bodies. We are beginning to understand how local signals from somatic support cells specify self-renewal versus differentiation in the stem cell niche at the apical tip of the testis. We are discovering the molecular events that block cell proliferation and initiate terminal differentiation at the switch from mitosis to meiosis-a signature event of the germ cell program. Our work is beginning to reveal how the developmental program that sets up the dramatic new cell type-specific transcription program that prepares germ cells for meiotic division and spermatid differentiation is turned on when cells become spermatocytes. I have had the privilege of working with incredible students, postdocs, and colleagues who have discovered, brainstormed, challenged, and refined our science and our ideas of how developmental pathways and cellular mechanisms work together to drive differentiation. © 2016 Elsevier Inc. All rights reserved.

Pathologic Stimulus Determines Lineage Commitment of Cardiac C-kit+ Cells.

Science.gov (United States)

Chen, Zhongming; Zhu, Wuqiang; Bender, Ingrid; Gong, Wuming; Kwak, Il-Youp; Yellamilli, Amritha; Hodges, Thomas J; Nemoto, Natsumi; Zhang, Jianyi; Garry, Daniel J; van Berlo, Jop H

2017-12-12

Although cardiac c-kit + cells are being tested in clinical trials, the circumstances that determine lineage differentiation of c-kit + cells in vivo are unknown. Recent findings suggest that endogenous cardiac c-kit + cells rarely contribute cardiomyocytes to the adult heart. We assessed whether various pathological stimuli differentially affect the eventual cell fates of c-kit + cells. We used single-cell sequencing and genetic lineage tracing of c-kit + cells to determine whether various pathological stimuli would result in different fates of c-kit + cells. Single-cell sequencing of cardiac CD45 - c-kit + cells showed innate heterogeneity, indicative of the existence of vascular and mesenchymal c-kit + cells in normal hearts. Cardiac pressure overload resulted in a modest increase in c-kit-derived cardiomyocytes, with significant increases in the numbers of endothelial cells and fibroblasts. Doxorubicin-induced acute cardiotoxicity did not increase c-kit-derived endothelial cell fates but instead induced cardiomyocyte differentiation. Mechanistically, doxorubicin-induced DNA damage in c-kit + cells resulted in expression of p53. Inhibition of p53 blocked cardiomyocyte differentiation in response to doxorubicin, whereas stabilization of p53 was sufficient to increase c-kit-derived cardiomyocyte differentiation. These results demonstrate that different pathological stimuli induce different cell fates of c-kit + cells in vivo. Although the overall rate of cardiomyocyte formation from c-kit + cells is still below clinically relevant levels, we show that p53 is central to the ability of c-kit + cells to adopt cardiomyocyte fates, which could lead to the development of strategies to preferentially generate cardiomyocytes from c-kit + cells. © 2017 American Heart Association, Inc.

Bridging the gap between postembryonic cell lineages and identified embryonic neuroblasts in the ventral nerve cord of Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Oliver Birkholz

2015-03-01

Full Text Available The clarification of complete cell lineages, which are produced by specific stem cells, is fundamental for understanding mechanisms, controlling the generation of cell diversity and patterning in an emerging tissue. In the developing Central Nervous System (CNS of Drosophila, neural stem cells (neuroblasts exhibit two periods of proliferation: During embryogenesis they produce primary lineages, which form the larval CNS. After a phase of mitotic quiescence, a subpopulation of them resumes proliferation in the larva to give rise to secondary lineages that build up the CNS of the adult fly. Within the ventral nerve cord (VNC detailed descriptions exist for both primary and secondary lineages. However, while primary lineages have been linked to identified neuroblasts, the assignment of secondary lineages has so far been hampered by technical limitations. Therefore, primary and secondary neural lineages co-existed as isolated model systems. Here we provide the missing link between the two systems for all lineages in the thoracic and abdominal neuromeres. Using the Flybow technique, embryonic neuroblasts were identified by their characteristic and unique lineages in the living embryo and their further development was traced into the late larval stage. This comprehensive analysis provides the first complete view of which embryonic neuroblasts are postembryonically reactivated along the anterior/posterior-axis of the VNC, and reveals the relationship between projection patterns of primary and secondary sublineages.

Impacts of Rac- and S-metolachlor on cyanobacterial cell integrity and release of microcystins at different nitrogen levels.

Science.gov (United States)

Wang, Jia; Zhang, Lijuan; Fan, Jiajia; Wen, Yuezhong

2017-08-01

Pesticide residues and nitrogen overload (which caused cyanobacteria blooms) have been two serious environmental concerns. In particular, chiral pesticides with different structures may have various impacts on cyanobacteria. Nitrogen may affect the behavior between pesticides and cyanobacteria (e.g., increase the adverse effects of pesticides on cyanobacteria). This study evaluated the impacts of Rac- and S-metolachlor on the cell integrity and toxin release of Microcystis aeruginosa cells at different nitrogen levels. The results showed that (both of the configurations: Rac-, S-) metolachlor could inhibit M. aeruginosa cell growth under most conditions, and the inhibition rates were increased with the growing concentrations of nitrogen and metolachlor. However, cyanobacterial growth was promoted in 48 h under environmental relevant condition (1 mg/L metolachlor and 0.15 mg/L nitrogen). Therefore, the water authorities should adjust the treatment parameters to remove possible larger numbers of cyaonbacteria under that condition. On the other hand, the inhibition degree of M. aeruginosa cell growth by S-metolachlor treatments was obviously larger than Rac-metolachlor treatments. S-metolachlor also had a stronger ability in compromising M. aeruginosa cells than Rac-metolachlor treatments. Compared to control samples, more extracellular toxins (12%-86% increases) were detected after 5 mg/L S-metolachlor treatment for 72 h at different nitrogen levels, but the variations of extracellular toxins caused by 5 mg/L Rac-metolachlor addition could be neglected. Consequently, higher concentrations of metolachlor in source waters are harmful to humans, but it may prevent cyanobacterial blooms. However, the potential risks (e.g. build-up of extracellular toxins) should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single-Cell Transcriptomic Analysis Defines Heterogeneity and Transcriptional Dynamics in the Adult Neural Stem Cell Lineage

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Ben W. Dulken

2017-01-01

Full Text Available Neural stem cells (NSCs in the adult mammalian brain serve as a reservoir for the generation of new neurons, oligodendrocytes, and astrocytes. Here, we use single-cell RNA sequencing to characterize adult NSC populations and examine the molecular identities and heterogeneity of in vivo NSC populations. We find that cells in the NSC lineage exist on a continuum through the processes of activation and differentiation. Interestingly, rare intermediate states with distinct molecular profiles can be identified and experimentally validated, and our analysis identifies putative surface markers and key intracellular regulators for these subpopulations of NSCs. Finally, using the power of single-cell profiling, we conduct a meta-analysis to compare in vivo NSCs and in vitro cultures, distinct fluorescence-activated cell sorting strategies, and different neurogenic niches. These data provide a resource for the field and contribute to an integrative understanding of the adult NSC lineage.

Decoding the DNA Methylome of Mantle Cell Lymphoma in the Light of the Entire B Cell Lineage

NARCIS (Netherlands)

Queirós, A.C. (Ana C.); R. Beekman (Renée); Vilarrasa-Blasi, R. (Roser); Duran-Ferrer, M. (Martí); Clot, G. (Guillem); Merkel, A. (Angelika); Raineri, E. (Emanuele); Russiñol, N. (Nuria); Castellano, G. (Giancarlo); S. Bea (Silvia); Navarro, A. (Alba); Kulis, M. (Marta); Verdaguer-Dot, N. (Núria); P. Jares (Pedro); A. Enjuanes (Anna); M.J. Calasanz (Maria); Bergmann, A. (Anke); Vater, I. (Inga); Salaverría, I. (Itziar); H.J.G. van de Werken (Harmen); W.H. Wilson (Wyndham); Datta, A. (Avik); P. Flicek (Paul); Royo, R. (Romina); J.H.A. Martens (Joost); Giné, E. (Eva); Lopez-Guillermo, A. (Armando); H. Stunnenberg (Henk); W. Klapper (Wolfram); C. Pott (Christiane); Heath, S. (Simon); I. Gut (Ivo); R. Siebert (Reiner); G. Campo (Gianluca); J.I. Martin-Subero (J.)

2016-01-01

textabstractWe analyzed the in silico purified DNA methylation signatures of 82 mantle cell lymphomas (MCL) in comparison with cell subpopulations spanning the entire B cell lineage. We identified two MCL subgroups, respectively carrying epigenetic imprints of germinal-center-inexperienced and

Cyanobacterial nitrogenases: phylogenetic diversity, regulation and functional predictions

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Alberto A. Esteves-Ferreira

2017-03-01

Full Text Available Abstract Cyanobacteria is a remarkable group of prokaryotic photosynthetic microorganisms, with several genera capable of fixing atmospheric nitrogen (N2 and presenting a wide range of morphologies. Although the nitrogenase complex is not present in all cyanobacterial taxa, it is spread across several cyanobacterial strains. The nitrogenase complex has also a high theoretical potential for biofuel production, since H2 is a by-product produced during N2 fixation. In this review we discuss the significance of a relatively wide variety of cell morphologies and metabolic strategies that allow spatial and temporal separation of N2 fixation from photosynthesis in cyanobacteria. Phylogenetic reconstructions based on 16S rRNA and nifD gene sequences shed light on the evolutionary history of the two genes. Our results demonstrated that (i sequences of genes involved in nitrogen fixation (nifD from several morphologically distinct strains of cyanobacteria are grouped in similarity with their morphology classification and phylogeny, and (ii nifD genes from heterocytous strains share a common ancestor. By using this data we also discuss the evolutionary importance of processes such as horizontal gene transfer and genetic duplication for nitrogenase evolution and diversification. Finally, we discuss the importance of H2 synthesis in cyanobacteria, as well as strategies and challenges to improve cyanobacterial H2 production.

Quantitative rather than qualitative differences in gene expression predominate in intestinal cell maturation along distinct cell lineages

International Nuclear Information System (INIS)

Velcich, Anna; Corner, Georgia; Paul, Doru; Zhuang Min; Mariadason, John M.; Laboisse, Christian; Augenlicht, Leonard

2005-01-01

Several cell types are present in the intestinal epithelium that likely arise from a common precursor, the stem cell, and each mature cell type expresses a unique set of genes that characterizes its functional phenotype. Although the process of differentiation is intimately linked to the cessation of proliferation, the mechanisms that dictate intestinal cell fate determination are not well characterized. To investigate the reprogramming of gene expression during the cell lineage allocation/differentiation process, we took advantage of a unique system of two clonal derivatives of HT29 cells, Cl16E and Cl19A cells, which spontaneously differentiate as mucus producing goblet and chloride-secreting cells, respectively, as a function of time. By profiling gene expression, we found that these two cell lines show remarkably similar kinetics of change in gene expression and common clusters of coordinately regulated genes. This demonstrates that lineage-specific differentiation of intestinal epithelial cells is characterized overall by the sequential recruitment of functionally similar gene sets independent of the final phenotype of the mature cells

Cell lineage analysis demonstrates an endodermal origin of the distal urethra and perineum.

Science.gov (United States)

Seifert, Ashley W; Harfe, Brian D; Cohn, Martin J

2008-06-01

Congenital malformations of anorectal and genitourinary (collectively, anogenital) organs occur at a high frequency in humans, however the lineage of cells that gives rise to anogenital organs remains poorly understood. The penile urethra has been reported to develop from two cell populations, with the proximal urethra developing from endoderm and the distal urethra forming from an apical ectodermal invagination, however this has never been tested by direct analysis of cell lineage. During gut development, endodermal cells express Sonic hedgehog (Shh), which is required for normal patterning of digestive and genitourinary organs. We have taken advantage of the properties of Shh expression to genetically label and follow the fate of posterior gut endoderm during anogenital development. We report that the entire urethra, including the distal (glandar) region, is derived from endoderm. Cloacal endoderm also gives rise to the epithelial linings of the bladder, rectum and anterior region of the anus. Surprisingly, the lineage map also revealed an endodermal origin of the perineum, which is the first demonstration that endoderm differentiates into skin. In addition, we fate mapped genital tubercle ectoderm and show that it makes no detectable contribution to the urethra. In males, formation of the urethral tube involves septation of the urethral plate by continued growth of the urorectal septum. Analysis of cell lineage following disruption of androgen signaling revealed that the urethral plate of flutamide-treated males does not undergo this septation event. Instead, urethral plate cells persist to the ventral margin of the tubercle, mimicking the pattern seen in females. Based on these spatial and temporal fate maps, we present a new model for anogenital development and suggest that disruptions at specific developmental time points can account for the association between anorectal and genitourinary defects.

Cyanobacterial biomass as carbohydrate and nutrient feedstock for bioethanol production by yeast fermentation

DEFF Research Database (Denmark)

Möllers, K Benedikt; Canella, D.; Jørgensen, Henning

2014-01-01

cyanobacterium Synechococcus sp. PCC 7002 was fermented using yeast into bioethanol. Results: The cyanobacterium accumulated a total carbohydrate content of about 60% of cell dry weight when cultivated under nitrate limitation. The cyanobacterial cells were harvested by centrifugation and subjected to enzymatic...... cyanobacteria or microalgae. Importantly, as well as fermentable carbohydrates, the cyanobacterial hydrolysate contained additional nutrients that promoted fermentation. This hydrolysate is therefore a promising substitute for the relatively expensive nutrient additives (such as yeast extract) commonly used...... hydrolysis using lysozyme and two alpha-glucanases. This enzymatic hydrolysate was fermented into ethanol by Saccharomyces cerevisiae without further treatment. All enzyme treatments and fermentations were carried out in the residual growth medium of the cyanobacteria with the only modification being that p...

The stream of precursors that colonizes the thymus proceeds selectively through the early T lineage precursor stage of T cell development

Science.gov (United States)

Benz, Claudia; Martins, Vera C.; Radtke, Freddy; Bleul, Conrad C.

2008-01-01

T cell development in the thymus depends on continuous colonization by hematopoietic precursors. Several distinct T cell precursors have been identified, but whether one or several independent precursor cell types maintain thymopoiesis is unclear. We have used thymus transplantation and an inducible lineage-tracing system to identify the intrathymic precursor cells among previously described thymus-homing progenitors that give rise to the T cell lineage in the thymus. Extrathymic precursors were not investigated in these studies. Both approaches show that the stream of T cell lineage precursor cells, when entering the thymus, selectively passes through the early T lineage precursor (ETP) stage. Immigrating precursor cells do not exhibit characteristics of double-negative (DN) 1c, DN1d, or DN1e stages, or of populations containing the common lymphoid precursor 2 (CLP-2) or the thymic equivalent of circulating T cell progenitors (CTPs). It remains possible that an unknown hematopoietic precursor cell or previously described extrathymic precursors with a CLP, CLP-2, or CTP phenotype feed into T cell development by circumventing known intrathymic T cell lineage progenitor cells. However, it is clear that of the known intrathymic precursors, only the ETP population contributes significant numbers of T lineage precursors to T cell development. PMID:18458114

Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells

Energy Technology Data Exchange (ETDEWEB)

Chow, Paik Wah [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Abdul Hamid, Zariyantey, E-mail: zyantey@ukm.edu.my [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Chan, Kok Meng [Environmental Health and Industrial Safety Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Inayat-Hussain, Salmaan Hussain [Environmental Health and Industrial Safety Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Rajab, Nor Fadilah [Biomedical Science Programme, School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Abdul Muda Aziz, 50300 Kuala Lumpur, Wilayah Persekutuan (Malaysia); Toxicology Laboratory, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia)

2015-04-01

Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24 h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e{sup +} cells but reduced the total counts of Sca-1{sup +}, CD11b{sup +}, Gr-1{sup +}, and CD45{sup +} cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5 μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12 μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage. - Highlights: • We examine 1,4-BQ toxicity targeting mouse hematopoietic cell lineages. • 1,4-BQ induces concentration-dependent cytotoxicity in bone marrow (BM) cells. • 1,4-BQ shows lineage-related toxicity on hematopoietic stem and

Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells

International Nuclear Information System (INIS)

Chow, Paik Wah; Abdul Hamid, Zariyantey; Chan, Kok Meng; Inayat-Hussain, Salmaan Hussain; Rajab, Nor Fadilah

2015-01-01

Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24 h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e + cells but reduced the total counts of Sca-1 + , CD11b + , Gr-1 + , and CD45 + cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5 μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12 μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage. - Highlights: • We examine 1,4-BQ toxicity targeting mouse hematopoietic cell lineages. • 1,4-BQ induces concentration-dependent cytotoxicity in bone marrow (BM) cells. • 1,4-BQ shows lineage-related toxicity on hematopoietic stem and progenitors. • 1,4-BQ

Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

Science.gov (United States)

Piontek, Marlena; Czyżewska, Wanda

2017-03-01

The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River (including Sławskie lake which is the beginning of the river), which is a source of drinking water for the inhabitants of Zielona Góra. In order to evaluate toxicity of cyanobacterial bloom it was conducted toxicological testing using aquatic invertebrates (Daphnia magna, Dugesia tigrina) and heterotrophic bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescens). Test samples were collected from May to October, 2012. The most toxic was a sample collected from Lake Sławskie on 20th October when cyanobacteria bloom with a predominance of Microcystis aeruginosa occurred and the amount of microcystins was the largest. The methanol extract of the sample was toxic only above a concentration of 6·103 mg·dm-3. The lethal concentration (48-h LC 50) for Daphnia magna was 3.09·103 and for Dugesia tigrina (240-h LC 50) 1.51·103 mg·dm-3 of microcystins (MC-LR, MC-YR and MC-RR). The same extract stimulated growth of Escherichia coli and Enterococcus faecalis cells.

Proteomic approaches in research of cyanobacterial photosynthesis.

Science.gov (United States)

Battchikova, Natalia; Angeleri, Martina; Aro, Eva-Mari

2015-10-01

Oxygenic photosynthesis in cyanobacteria, algae, and plants is carried out by a fabulous pigment-protein machinery that is amazingly complicated in structure and function. Many different approaches have been undertaken to characterize the most important aspects of photosynthesis, and proteomics has become the essential component in this research. Here we describe various methods which have been used in proteomic research of cyanobacteria, and demonstrate how proteomics is implemented into on-going studies of photosynthesis in cyanobacterial cells.

IL-4/IL-13 Signaling Inhibits the Potential of Early Thymic Progenitors To Commit to the T Cell Lineage.

Science.gov (United States)

Barik, Subhasis; Miller, Mindy M; Cattin-Roy, Alexis N; Ukah, Tobechukwu K; Chen, Weirong; Zaghouani, Habib

2017-10-15

Early thymic progenitors (ETPs) are endowed with diverse potencies and can give rise to myeloid and lymphoid lineage progenitors. How the thymic environment guides ETP commitment and maturation toward a specific lineage remains obscure. We have previously shown that ETPs expressing the heteroreceptor (HR) comprising IL-4Rα and IL-13Rα1 give rise to myeloid cells but not T cells. In this article, we show that signaling through the HR inhibits ETP maturation to the T cell lineage but enacts commitment toward the myeloid cells. Indeed, HR + ETPs, but not HR - ETPs, exhibit activated STAT6 transcription factor, which parallels with downregulation of Notch1, a critical factor for T cell development. Meanwhile, the myeloid-specific transcription factor C/EBPα, usually under the control of Notch1, is upregulated. Furthermore, in vivo inhibition of STAT6 phosphorylation restores Notch1 expression in HR + ETPs, which regain T lineage potential. In addition, upon stimulation with IL-4 or IL-13, HR - ETPs expressing virally transduced HR also exhibit STAT6 phosphorylation and downregulation of Notch1, leading to inhibition of lymphoid, but not myeloid, lineage potential. These observations indicate that environmental cytokines play a role in conditioning ETP lineage choice, which would impact T cell development. Copyright © 2017 by The American Association of Immunologists, Inc.

Developmental origin and lineage plasticity of endogenous cardiac stem cells

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Santini, Maria Paola; Forte, Elvira; Harvey, Richard P.; Kovacic, Jason C.

2016-01-01

Over the past two decades, several populations of cardiac stem cells have been described in the adult mammalian heart. For the most part, however, their lineage origins and in vivo functions remain largely unexplored. This Review summarizes what is known about different populations of embryonic and adult cardiac stem cells, including KIT+, PDGFRα+, ISL1+ and SCA1+ cells, side population cells, cardiospheres and epicardial cells. We discuss their developmental origins and defining characteristics, and consider their possible contribution to heart organogenesis and regeneration. We also summarize the origin and plasticity of cardiac fibroblasts and circulating endothelial progenitor cells, and consider what role these cells have in contributing to cardiac repair. PMID:27095490

State of knowledge and concerns on cyanobacterial blooms and cyanotoxins.

Science.gov (United States)

Merel, Sylvain; Walker, David; Chicana, Ruth; Snyder, Shane; Baurès, Estelle; Thomas, Olivier

2013-09-01

Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical

Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

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Piontek Marlena

2017-03-01

Full Text Available The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River (including Sławskie lake which is the beginning of the river, which is a source of drinking water for the inhabitants of Zielona Góra. In order to evaluate toxicity of cyanobacterial bloom it was conducted toxicological testing using aquatic invertebrates (Daphnia magna, Dugesia tigrina and heterotrophic bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescens. Test samples were collected from May to October, 2012. The most toxic was a sample collected from Lake Sławskie on 20th October when cyanobacteria bloom with a predominance of Microcystis aeruginosa occurred and the amount of microcystins was the largest. The methanol extract of the sample was toxic only above a concentration of 6·103 mg·dm-3. The lethal concentration (48-h LC 50 for Daphnia magna was 3.09·103 and for Dugesia tigrina (240-h LC 50 1.51·103 mg·dm-3 of microcystins (MC-LR, MC-YR and MC-RR. The same extract stimulated growth of Escherichia coli and Enterococcus faecalis cells.

Identification and Characterization of Mouse Otic Sensory Lineage Genes

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Byron H. Hartman

2015-03-01

Full Text Available Vertebrate embryogenesis gives rise to all cell types of an organism through the development of many unique lineages derived from the three primordial germ layers. The otic sensory lineage arises from the otic vesicle, a structure formed through invagination of placodal non-neural ectoderm. This developmental lineage possesses unique differentiation potential, giving rise to otic sensory cell populations including hair cells, supporting cells, and ganglion neurons of the auditory and vestibular organs. Here we present a systematic approach to identify transcriptional features that distinguish the otic sensory lineage (from early otic progenitors to otic sensory populations from other major lineages of vertebrate development. We used a microarray approach to analyze otic sensory lineage populations including microdissected otic vesicles (embryonic day 10.5 as well as isolated neonatal cochlear hair cells and supporting cells at postnatal day 3. Non-otic tissue samples including periotic tissues and whole embryos with otic regions removed were used as reference populations to evaluate otic specificity. Otic populations shared transcriptome-wide correlations in expression profiles that distinguish members of this lineage from non-otic populations. We further analyzed the microarray data using comparative and dimension reduction methods to identify individual genes that are specifically expressed in the otic sensory lineage. This analysis identified and ranked top otic sensory lineage-specific transcripts including Fbxo2, Col9a2, and Oc90, and additional novel otic lineage markers. To validate these results we performed expression analysis on select genes using immunohistochemistry and in situ hybridization. Fbxo2 showed the most striking pattern of specificity to the otic sensory lineage, including robust expression in the early otic vesicle and sustained expression in prosensory progenitors and auditory and vestibular hair cells and supporting

TET proteins regulate the lineage specification and TCR-mediated expansion of iNKT cells.

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Tsagaratou, Ageliki; González-Avalos, Edahí; Rautio, Sini; Scott-Browne, James P; Togher, Susan; Pastor, William A; Rothenberg, Ellen V; Chavez, Lukas; Lähdesmäki, Harri; Rao, Anjana

2017-01-01

TET proteins oxidize 5-methylcytosine in DNA to 5-hydroxymethylcytosine and other oxidation products. We found that simultaneous deletion of Tet2 and Tet3 in mouse CD4 + CD8 + double-positive thymocytes resulted in dysregulated development and proliferation of invariant natural killer T cells (iNKT cells). Tet2-Tet3 double-knockout (DKO) iNKT cells displayed pronounced skewing toward the NKT17 lineage, with increased DNA methylation and impaired expression of genes encoding the key lineage-specifying factors T-bet and ThPOK. Transfer of purified Tet2-Tet3 DKO iNKT cells into immunocompetent recipient mice resulted in an uncontrolled expansion that was dependent on the nonclassical major histocompatibility complex (MHC) protein CD1d, which presents lipid antigens to iNKT cells. Our data indicate that TET proteins regulate iNKT cell fate by ensuring their proper development and maturation and by suppressing aberrant proliferation mediated by the T cell antigen receptor (TCR).

A coagulation-powdered activated carbon-ultrafiltration - Multiple barrier approach for removing toxins from two Australian cyanobacterial blooms

International Nuclear Information System (INIS)

Dixon, Mike B.; Richard, Yann; Ho, Lionel; Chow, Christopher W.K.; O'Neill, Brian K.; Newcombe, Gayle

2011-01-01

Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition.

Generation of polyhormonal and multipotent pancreatic progenitor lineages from human pluripotent stem cells.

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Korytnikov, Roman; Nostro, Maria Cristina

2016-05-15

Generation of pancreatic β-cells from human pluripotent stem cells (hPSCs) has enormous importance in type 1 diabetes (T1D), as it is fundamental to a treatment strategy based on cellular therapeutics. Being able to generate β-cells, as well as other mature pancreatic cells, from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) will also enable the development of platforms that can be used for disease modeling and drug testing for a variety of pancreas-associated diseases, including cystic fibrosis. For this to occur, it is crucial to develop differentiation strategies that are robust and reproducible across cell lines and laboratories. In this article we describe two serum-free differentiation protocols designed to generate specific pancreatic lineages from hPSCs. Our approach employs a variety of cytokines and small molecules to mimic developmental pathways active during pancreatic organogenesis and allows for the in vitro generation of distinct pancreatic populations. The first protocol is designed to give rise to polyhormonal cells that have the potential to differentiate into glucagon-producing cells. The second protocol is geared to generate multipotent pancreatic progenitor cells, which harbor the potential to generate all pancreatic lineages including: monohormonal endocrine cells, acinar, and ductal cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Cyanobacterial chassis engineering for enhancing production of biofuels and chemicals.

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Gao, Xinyan; Sun, Tao; Pei, Guangsheng; Chen, Lei; Zhang, Weiwen

2016-04-01

To reduce dependence on fossil fuels and curb greenhouse effect, cyanobacteria have emerged as an important chassis candidate for producing biofuels and chemicals due to their capability to directly utilize sunlight and CO2 as the sole energy and carbon sources, respectively. Recent progresses in developing and applying various synthetic biology tools have led to the successful constructions of novel pathways of several dozen green fuels and chemicals utilizing cyanobacterial chassis. Meanwhile, it is increasingly recognized that in order to enhance productivity of the synthetic cyanobacterial systems, optimizing and engineering more robust and high-efficient cyanobacterial chassis should not be omitted. In recent years, numerous research studies have been conducted to enhance production of green fuels and chemicals through cyanobacterial chassis modifications involving photosynthesis, CO2 uptake and fixation, products exporting, tolerance, and cellular regulation. In this article, we critically reviewed recent progresses and universal strategies in cyanobacterial chassis engineering to make it more robust and effective for bio-chemicals production.

Cyanobacterial defense mechanisms against foreign DNA transfer and their impact on genetic engineering

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Karina Stucken

2013-01-01

Full Text Available Cyanobacteria display a large diversity of cellular forms ranging from unicellular to complex multicellular filaments or aggregates. Species in the group present a wide range of metabolic characteristics including the fixation of atmospheric nitrogen, resistance to extreme environments, production of hydrogen, secondary metabolites and exopolysaccharides. These characteristics led to the growing interest in cyanobacteria across the fields of ecology, evolution, cell biology and biotechnology. The number of available cyanobacterial genome sequences has increased considerably in recent years, with more than 140 fully sequenced genomes to date. Genetic engineering of cyanobacteria is widely applied to the model unicellular strains Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. However the establishment of transformation protocols in many other cyanobacterial strains is challenging. One obstacle to the development of these novel model organisms is that many species have doubling times of 48 h or more, much longer than the bacterial models E. coli or B. subtilis. Furthermore, cyanobacterial defense mechanisms against foreign DNA pose a physical and biochemical barrier to DNA insertion in most strains. Here we review the various barriers to DNA uptake in the context of lateral gene transfer among microbes and the various mechanisms for DNA acquisition within the prokaryotic domain. Understanding the cyanobacterial defense mechanisms is expected to assist in the development and establishment of novel transformation protocols that are specifically suitable for this group.

B lymphocyte lineage cells and the respiratory system

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Kato, Atsushi; Hulse, Kathryn E.; Tan, Bruce K.; Schleimer, Robert P.

2013-01-01

Adaptive humoral immune responses in the airways are mediated by B cells and plasma cells that express highly evolved and specific receptors and produce immunoglobulins of most isotypes. In some cases, such as autoimmune diseases or inflammatory diseases caused by excessive exposure to foreign antigens, these same immune cells can cause disease by virtue of overly vigorous responses. This review discusses the generation, differentiation, signaling, activation and recruitment pathways of B cells and plasma cells, with special emphasis on unique characteristics of subsets of these cells functioning within the respiratory system. The primary sensitization events that generate B cells responsible for effector responses throughout the airways usually occur in the upper airways, in tonsils and adenoid structures that make up Waldeyer’s Ring. Upon secondary exposure to antigen in the airways, antigen-processing dendritic cells migrate into secondary lymphoid organs such as lymph nodes that drain the upper and lower airways and further B cell expansion takes place at those sites. Antigen exposure in the upper or lower airways can also drive expansion of B lineage cells in the airway mucosal tissue and lead to the formation of inducible lymphoid follicles or aggregates that can mediate local immunity or disease. PMID:23540615

SHIP1-expressing mesenchymal stem cells regulate hematopoietic stem cell homeostasis and lineage commitment during aging.

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Iyer, Sonia; Brooks, Robert; Gumbleton, Matthew; Kerr, William G

2015-05-01

Hematopoietic stem cell (HSC) self-renewal and lineage choice are subject to intrinsic control. However, this intrinsic regulation is also impacted by external cues provided by niche cells. There are multiple cellular components that participate in HSC support with the mesenchymal stem cell (MSC) playing a pivotal role. We had previously identified a role for SH2 domain-containing inositol 5'-phosphatase-1 (SHIP1) in HSC niche function through analysis of mice with germline or induced SHIP1 deficiency. In this study, we show that the HSC compartment expands significantly when aged in a niche that contains SHIP1-deficient MSC; however, this expanded HSC compartment exhibits a strong bias toward myeloid differentiation. In addition, we show that SHIP1 prevents chronic G-CSF production by the aging MSC compartment. These findings demonstrate that intracellular signaling by SHIP1 in MSC is critical for the control of HSC output and lineage commitment during aging. These studies increase our understanding of how myeloid bias occurs in aging and thus could have implications for the development of myeloproliferative disease in aging.

Differential tolerance to cyanobacterial exposure between geographically distinct populations of Perca fluviatilis.

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Persson, Karl-Johan; Bergström, Kristofer; Mazur-Marzec, Hannah; Legrand, Catherine

2013-12-15

Toxic cyanobacterial blooms are an important problem worldwide. Cyanobacteria may negatively impact young-of-the-year (YOY) fish directly (toxin production, turbidity, decrease in water quality) or indirectly (trophic toxin transfer, changes in prey species composition). Here we test whether there are any differences in cyanobacterial tolerance between four geographically distinct populations of European perch (Perca fluviatilis). We show that P. fluviatilis may develop tolerance against cyanobacteria demonstrated by the ability of individuals from a marine site (exposed to annual cyanobacterial blooms) to increase their detoxification more than individuals from an oligotrophic site (rarely exposed to cyanobacteria). Our results also revealed significant interaction effects between genotypes within a population and response to cyanobacterial exposure in terms of absolute growth and detoxification activity. This genotype by treatment interaction may result in local adaptations to cyanobacterial exposure in P. fluviatilis. Hence, the sensitivity against cyanobacterial exposure may differ between within species populations increasing the importance of local management of fish populations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Th17-lineage cells in pulmonary sarcoidosis and Löfgren's syndrome: Friend or foe?

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Miedema, Jelle R; Kaiser, Ylva; Broos, Caroline E; Wijsenbeek, Marlies S; Grunewald, Johan; Kool, Mirjam

2018-02-01

Sarcoidosis, a multisystem granulomatous disorder, has historically been classified as Th1-driven disease. However, increasing data demonstrate a key role of Th17-cell plasticity in granuloma formation and maintenance. In Löfgren's syndrome (LS), an acute and distinct phenotype of sarcoidosis with a favorable outcome, differences in Th17-lineage cell subsets, cytokine expression and T-cell suppressive mechanisms may account for differences in clinical presentation as well as prognosis compared to non-LS sarcoidosis. In contrast with LS, up to 20% of non-LS sarcoidosis patients may progress to irreversible pulmonary fibrosis. In non-LS sarcoidosis patients, IFN-γ-producing Th17.1-cells appear to be more pathogenic and possibly linked to disease progression, while a broader range of cytokines is found in bronchoalveolar lavage fluid (BALF) in LS patients. Differences in Cytotoxic T-lymphocyte antigen 4 (CTLA-4) expression on Th17-cells and regulatory T-cells (Treg) could contribute to Th17-cell pathogenicity and consequently to either disease resolution or ongoing inflammation in sarcoidosis. Furthermore, several genes and SNPs are associated with disease susceptibility and outcome in sarcoidosis, the majority of which are involved in antigen presentation, T-cell activation or regulation of T-cell survival. Novel insights into the role of Th17-cells in the pathogenesis of both LS and non-LS sarcoidosis will unravel pathogenic and benign Th17-lineage cell function and drivers of Th17-cell plasticity. This will also help identify new treatment strategies for LS and non-LS sarcoidosis patients by altering Th17-cell activation, suppress conversion into more pathogenic subtypes, or influence cytokine signaling towards a beneficial signature of Th17-lineage cells. In this review, we summarize new insights into Th17-cell plasticity in the complex pathogenesis of sarcoidosis and connect these cells to the different disease phenotypes, discuss the role of genetic

Functional profiling of cyanobacterial genomes and its role in ecological adaptations

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Ratna Prabha

2016-09-01

Full Text Available With the availability of complete genome sequences of many cyanobacterial species, it is becoming feasible to study the broad prospective of the environmental adaptation and the overall changes at transcriptional and translational level in these organisms. In the evolutionary phase, niche-specific competitive forces have resulted in specific features of the cyanobacterial genomes. In this study, functional composition of the 84 different cyanobacterial genomes and their adaptations to different environments was examined by identifying the genomic composition for specific cellular processes, which reflect their genomic functional profile and ecological adaptation. It was identified that among cyanobacterial genomes, metabolic genes have major share over other categories and differentiation of genomic functional profile was observed for the species inhabiting different habitats. The cyanobacteria of freshwater and other habitats accumulate large number of poorly characterized genes. Strain specific functions were also reported in many cyanobacterial members, of which an important feature was the occurrence of phage-related sequences. From this study, it can be speculated that habitat is one of the major factors in giving the shape of functional composition of cyanobacterial genomes towards their ecological adaptations.

Dynamics of a cyanobacterial bloom in a hypereutrophic reservoir ...

African Journals Online (AJOL)

Blooming and non-blooming periods between 2004 and 2006 in a hypereutrophic reservoir, where cyanobacterial blooms have previously been reported to be permanent, presented an opportunity to characterise factors that may favour cyanobacterial dominance. As a bloom developed in May 2004, a shift to dominance by ...

First report of cyanobacterial diversity and microcystins in a ...

African Journals Online (AJOL)

The cyanobacterial diversity of Sidi Boughaba, a Moroccan coastal lagoon and Ramsar site, was evaluated and its potentially toxic species were isolated and characterised. This study was the first time that cyanobacterial diversity and cyanotoxin production have been characterised in a Moroccan coastal lagoon. Samples ...

A mex3 homolog is required for differentiation during planarian stem cell lineage development

Science.gov (United States)

Zhu, Shu Jun; Hallows, Stephanie E; Currie, Ko W; Xu, ChangJiang; Pearson, Bret J

2015-01-01

Neoblasts are adult stem cells (ASCs) in planarians that sustain cell replacement during homeostasis and regeneration of any missing tissue. While numerous studies have examined genes underlying neoblast pluripotency, molecular pathways driving postmitotic fates remain poorly defined. In this study, we used transcriptional profiling of irradiation-sensitive and irradiation-insensitive cell populations and RNA interference (RNAi) functional screening to uncover markers and regulators of postmitotic progeny. We identified 32 new markers distinguishing two main epithelial progenitor populations and a planarian homolog to the MEX3 RNA-binding protein (Smed-mex3-1) as a key regulator of lineage progression. mex3-1 was required for generating differentiated cells of multiple lineages, while restricting the size of the stem cell compartment. We also demonstrated the utility of using mex3-1(RNAi) animals to identify additional progenitor markers. These results identified mex3-1 as a cell fate regulator, broadly required for differentiation, and suggest that mex3-1 helps to mediate the balance between ASC self-renewal and commitment. DOI: http://dx.doi.org/10.7554/eLife.07025.001 PMID:26114597

A novel lineage of myoviruses infecting cyanobacteria is widespread in the oceans.

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Sabehi, Gazalah; Shaulov, Lihi; Silver, David H; Yanai, Itai; Harel, Amnon; Lindell, Debbie

2012-02-07

Viruses infecting bacteria (phages) are thought to greatly impact microbial population dynamics as well as the genome diversity and evolution of their hosts. Here we report on the discovery of a novel lineage of tailed dsDNA phages belonging to the family Myoviridae and describe its first representative, S-TIM5, that infects the ubiquitous marine cyanobacterium, Synechococcus. The genome of this phage encodes an entirely unique set of structural proteins not found in any currently known phage, indicating that it uses lineage-specific genes for virion morphogenesis and represents a previously unknown lineage of myoviruses. Furthermore, among its distinctive collection of replication and DNA metabolism genes, it carries a mitochondrial-like DNA polymerase gene, providing strong evidence for the bacteriophage origin of the mitochondrial DNA polymerase. S-TIM5 also encodes an array of bacterial-like metabolism genes commonly found in phages infecting cyanobacteria including photosynthesis, carbon metabolism and phosphorus acquisition genes. This suggests a common gene pool and gene swapping of cyanophage-specific genes among different phage lineages despite distinct sets of structural and replication genes. All cytosines following purine nucleotides are methylated in the S-TIM5 genome, constituting a unique methylation pattern that likely protects the genome from nuclease degradation. This phage is abundant in the Red Sea and S-TIM5 gene homologs are widespread in the oceans. This unusual phage type is thus likely to be an important player in the oceans, impacting the population dynamics and evolution of their primary producing cyanobacterial hosts.

Self-organization is a dynamic and lineage-intrinsic property of mammary epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Chanson, L. [Ecole Polytechnique Federale de Lausanne (Switzerland). Inst. of Bioengineering; Brownfield, D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Univ. of California, Berkeley, CA (United States). Dept. of Bioengineering; Garbe, J. C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Kuhn, I. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Stampfer, M. R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Bissell, M. J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; LaBarge, M. A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.

2011-02-07

Loss of organization is a principle feature of cancers; therefore it is important to understand how normal adult multilineage tissues, such as bilayered secretory epithelia, establish and maintain their architectures. The self-organization process that drives heterogeneous mixtures of cells to form organized tissues is well studied in embryology and with mammalian cell lines that were abnormal or engineered. Here we used a micropatterning approach that confined cells to a cylindrical geometry combined with an algorithm to quantify changes of cellular distribution over time to measure the ability of different cell types to self-organize relative to each other. Using normal human mammary epithelial cells enriched into pools of the two principal lineages, luminal and myoepithelial cells, we demonstrated that bilayered organization in mammary epithelium was driven mainly by lineage-specific differential E-cadherin expression, but that P-cadherin contributed specifically to organization of the myoepithelial layer. Disruption of the actomyosin network or of adherens junction proteins resulted in either prevention of bilayer formation or loss of preformed bilayers, consistent with continual sampling of the local microenvironment by cadherins. Together these data show that self-organization is an innate and reversible property of communities of normal adult human mammary epithelial cells.

DNA Methyltransferases Modulate Hepatogenic Lineage Plasticity of Mesenchymal Stromal Cells

Directory of Open Access Journals (Sweden)

Chien-Wei Lee

2017-07-01

Full Text Available The irreversibility of developmental processes in mammalian cells has been challenged by rising evidence that de-differentiation of hepatocytes occurs in adult liver. However, whether reversibility exists in mesenchymal stromal cell (MSC-derived hepatocytes (dHeps remains elusive. In this study, we find that hepatogenic differentiation (HD of MSCs is a reversible process and is modulated by DNA methyltransferases (DNMTs. DNMTs are regulated by transforming growth factor β1 (TGFβ1, which in turn controls hepatogenic differentiation and de-differentiation. In addition, a stepwise reduction in TGFβ1 concentrations in culture media increases DNMT1 and decreases DNMT3 in primary hepatocytes (Heps and confers Heps with multi-differentiation potentials similarly to MSCs. Hepatic lineage reversibility of MSCs and lineage conversion of Heps are regulated by DNMTs in response to TGFβ1. This previously unrecognized TGFβ1-DNMTs-MSC-HD axis may further increase the understanding the normal and pathological processes in the liver, as well as functions of MSCs after transplantation to treat liver diseases.

Adipogenic placenta-derived mesenchymal stem cells are not lineage restricted by withdrawing extrinsic factors: developing a novel visual angle in stem cell biology.

Science.gov (United States)

Hu, C; Cao, H; Pan, X; Li, J; He, J; Pan, Q; Xin, J; Yu, X; Li, J; Wang, Y; Zhu, D; Li, L

2016-03-17

Current evidence implies that differentiated bone marrow mesenchymal stem cells (BMMSCs) can act as progenitor cells and transdifferentiate across lineage boundaries. However, whether this unrestricted lineage has specificities depending on the stem cell type is unknown. Placental-derived mesenchymal stem cells (PDMSCs), an easily accessible and less invasive source, are extremely useful materials in current stem cell therapies. No studies have comprehensively analyzed the transition in morphology, surface antigens, metabolism and multilineage potency of differentiated PDMSCs after their dedifferentiation. In this study, we showed that after withdrawing extrinsic factors, adipogenic PDMSCs reverted to a primitive cell population and retained stem cell characteristics. The mitochondrial network during differentiation and dedifferentiation may serve as a marker of absent or acquired pluripotency in various stem cell models. The new population proliferated faster than unmanipulated PDMSCs and could be differentiated into adipocytes, osteocytes and hepatocytes. The cell adhesion molecules (CAMs) signaling pathway and extracellular matrix (ECM) components modulate cell behavior and enable the cells to proliferate or differentiate during the differentiation, dedifferentiation and redifferentiation processes in our study. These observations indicate that the dedifferentiated PDMSCs are distinguishable from the original PDMSCs and may serve as a novel source in stem cell biology and cell-based therapeutic strategies. Furthermore, whether PDMSCs differentiated into other lineages can be dedifferentiated to a primitive cell population needs to be investigated.

Instruction of hematopoietic lineage choice by cytokine signaling

Energy Technology Data Exchange (ETDEWEB)

Endele, Max; Etzrodt, Martin; Schroeder, Timm, E-mail: timm.schroeder@bsse.ethz.ch

2014-12-10

Hematopoiesis is the cumulative consequence of finely tuned signaling pathways activated through extrinsic factors, such as local niche signals and systemic hematopoietic cytokines. Whether extrinsic factors actively instruct the lineage choice of hematopoietic stem and progenitor cells or are only selectively allowing survival and proliferation of already intrinsically lineage-committed cells has been debated over decades. Recent results demonstrated that cytokines can instruct lineage choice. However, the precise function of individual cytokine-triggered signaling molecules in inducing cellular events like proliferation, lineage choice, and differentiation remains largely elusive. Signal transduction pathways activated by different cytokine receptors are highly overlapping, but support the production of distinct hematopoietic lineages. Cellular context, signaling dynamics, and the crosstalk of different signaling pathways determine the cellular response of a given extrinsic signal. New tools to manipulate and continuously quantify signaling events at the single cell level are therefore required to thoroughly interrogate how dynamic signaling networks yield a specific cellular response. - Highlights: • Recent studies provided definite proof for lineage-instructive action of cytokines. • Signaling pathways involved in hematopoietic lineage instruction remain elusive. • New tools are emerging to quantitatively study dynamic signaling networks over time.

Optical Imaging for Stem Cell Differentiation to Neuronal Lineage

International Nuclear Information System (INIS)

Hwang, Do Won; Lee, Dong Soo

2012-01-01

In regenerative medicine, the prospect of stem cell therapy hold great promise for the recovery of injured tissues and effective treatment of intractable diseases. Tracking stem cell fate provides critical information to understand and evaluate the success of stem cell therapy. The recent emergence of in vivo noninvasive molecular imaging has enabled assessment of the behavior of grafted stem cells in living subjects. In this review, we provide an overview of current optical imaging strategies based on cell or tissue specific reporter gene expression and of in vivo methods to monitor stem cell differentiation into neuronal lineages. These methods use optical reporters either regulated by neuron-specific promoters or containing neuron-specific microRNA binding sites. Both systems revealed dramatic changes in optical reporter imaging signals in cells differentiating a yeast GAL4 amplification system or an engineering-enhanced luciferase reported gene. Furthermore, we propose an advanced imaging system to monitor neuronal differentiation during neurogenesis that uses in vivo multiplexed imaging techniques capable of detecting several targets simultaneously

Characterization of glucose‐related metabolic pathways in differentiated rat oligodendrocyte lineage cells

Science.gov (United States)

Amaral, Ana I.; Hadera, Mussie G.; Tavares, Joana M.

2015-01-01

Although oligodendrocytes constitute a significant proportion of cells in the central nervous system (CNS), little is known about their intermediary metabolism. We have, therefore, characterized metabolic functions of primary oligodendrocyte precursor cell cultures at late stages of differentiation using isotope‐labelled metabolites. We report that differentiated oligodendrocyte lineage cells avidly metabolize glucose in the cytosol and pyruvate derived from glucose in the mitochondria. The labelling patterns of metabolites obtained after incubation with [1,2‐13C]glucose demonstrated that the pentose phosphate pathway (PPP) is highly active in oligodendrocytes (approximately 10% of glucose is metabolized via the PPP as indicated by labelling patterns in phosphoenolpyruvate). Mass spectrometry and magnetic resonance spectroscopy analyses of metabolites after incubation of cells with [1‐13C]lactate or [1,2‐13C]glucose, respectively, demonstrated that anaplerotic pyruvate carboxylation, which was thought to be exclusive to astrocytes, is also active in oligodendrocytes. Using [1,2‐13C]acetate, we show that oligodendrocytes convert acetate into acetyl CoA which is metabolized in the tricarboxylic acid cycle. Analysis of labelling patterns of alanine after incubation of cells with [1,2‐13C]acetate and [1,2‐13C]glucose showed catabolic oxidation of malate or oxaloacetate. In conclusion, we report that oligodendrocyte lineage cells at late differentiation stages are metabolically highly active cells that are likely to contribute considerably to the metabolic activity of the CNS. GLIA 2016;64:21–34 PMID:26352325

Y-chromosome lineage determines cardiovascular organ T-cell infiltration in the stroke-prone spontaneously hypertensive rat.

Science.gov (United States)

Khan, Shanzana I; Andrews, Karen L; Jackson, Kristy L; Memon, Basimah; Jefferis, Ann-Maree; Lee, Man K S; Diep, Henry; Wei, Zihui; Drummond, Grant R; Head, Geoffrey A; Jennings, Garry L; Murphy, Andrew J; Vinh, Antony; Sampson, Amanda K; Chin-Dusting, Jaye P F

2018-05-01

The essential role of the Y chromosome in male sex determination has largely overshadowed the possibility that it may exert other biologic roles. Here, we show that Y-chromosome lineage is a strong determinant of perivascular and renal T-cell infiltration in the stroke-prone spontaneously hypertensive rat, which, in turn, may influence vascular function and blood pressure (BP). We also show, for the first time to our knowledge, that augmented perivascular T-cell levels can directly instigate vascular dysfunction, and that the production of reactive oxygen species that stimulate cyclo-oxygenase underlies this. We thus provide strong evidence for the consideration of Y-chromosome lineage in the diagnosis and treatment of male hypertension, and point to the modulation of cardiovascular organ T-cell infiltration as a possible mechanism that underpins Y- chromosome regulation of BP.-Khan, S. I., Andrews, K. L., Jackson, K. L., Memon, B., Jefferis, A.-M., Lee, M. K. S., Diep, H., Wei, Z., Drummond, G. R., Head, G. A., Jennings, G. L., Murphy, A. J., Vinh, A., Sampson, A. K., Chin-Dusting, J. P. F. Y-chromosome lineage determines cardiovascular organ T-cell infiltration in the stroke-prone spontaneously hypertensive rat.

Luminal progenitors restrict their lineage potential during mammary gland development.

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Rodilla, Veronica; Dasti, Alessandro; Huyghe, Mathilde; Lafkas, Daniel; Laurent, Cécile; Reyal, Fabien; Fre, Silvia

2015-02-01

The hierarchical relationships between stem cells and progenitors that guide mammary gland morphogenesis are still poorly defined. While multipotent basal stem cells have been found within the myoepithelial compartment, the in vivo lineage potential of luminal progenitors is unclear. Here we used the expression of the Notch1 receptor, previously implicated in mammary gland development and tumorigenesis, to elucidate the hierarchical organization of mammary stem/progenitor cells by lineage tracing. We found that Notch1 expression identifies multipotent stem cells in the embryonic mammary bud, which progressively restrict their lineage potential during mammary ductal morphogenesis to exclusively generate an ERαneg luminal lineage postnatally. Importantly, our results show that Notch1-labelled cells represent the alveolar progenitors that expand during pregnancy and survive multiple successive involutions. This study reveals that postnatal luminal epithelial cells derive from distinct self-sustained lineages that may represent the cells of origin of different breast cancer subtypes.

Comprehensive evaluation of leukocyte lineage derived from human hematopoietic cells in humanized mice.

Science.gov (United States)

Takahashi, Masayuki; Tsujimura, Noriyuki; Otsuka, Kensuke; Yoshino, Tomoko; Mori, Tetsushi; Matsunaga, Tadashi; Nakasono, Satoshi

2012-04-01

Recently, humanized animals whereby a part of the animal is biologically engineered using human genes or cells have been utilized to overcome interspecific differences. Herein, we analyzed the detail of the differentiation states of various human leukocyte subpopulations in humanized mouse and evaluated comprehensively the similarity of the leukocyte lineage between humanized mice and humans. Humanized mice were established by transplanting human CD34(+) cord blood cells into irradiated severely immunodeficient NOD/Shi-scid/IL2Rγ(null) (NOG) mice, and the phenotypes of human cells contained in bone marrow, thymus, spleen and peripheral blood from the mice were analyzed at monthly intervals until 4 months after cell transplantation. The analysis revealed that transplanted human hematopoietic stem cells via the caudal vein homed and engrafted themselves successfully at the mouse bone marrow. Subsequently, the differentiated leukocytes migrated to the various tissues. Almost all of the leukocytes within the thymus were human cells. Furthermore, analysis of the differentiation states of human leukocytes in various tissues and organs indicated that it is highly likely that the human-like leukocyte lineage can be developed in mice. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

On the use of metabolic control analysis in the optimization of cyanobacterial biosolar cell factories.

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Angermayr, S Andreas; Hellingwerf, Klaas J

2013-09-26

Oxygenic photosynthesis will have a key role in a sustainable future. It is therefore significant that this process can be engineered in organisms such as cyanobacteria to construct cell factories that catalyze the (sun)light-driven conversion of CO2 and water into products like ethanol, butanol, or other biofuels or lactic acid, a bioplastic precursor, and oxygen as a byproduct. It is of key importance to optimize such cell factories to maximal efficiency. This holds for their light-harvesting capabilities under, for example, circadian illumination in large-scale photobioreactors. However, this also holds for the "dark" reactions of photosynthesis, that is, the conversion of CO2, NADPH, and ATP into a product. Here, we present an analysis, based on metabolic control theory, to estimate the optimal capacity for product formation with which such cyanobacterial cell factories have to be equipped. Engineered l-lactic acid producing Synechocystis sp. PCC6803 strains are used to identify the relation between production rate and enzymatic capacity. The analysis shows that the engineered cell factories for l-lactic acid are fully limited by the metabolic capacity of the product-forming pathway. We attribute this to the fact that currently available promoter systems in cyanobacteria lack the genetic capacity to a provide sufficient expression in single-gene doses.

Cyanobacterial Occurrence and Diversity in Seagrass Meadows in ...

African Journals Online (AJOL)

Oscillatoria, Lyngbya and Spirulina were the dominant cyanobacterial genera. Cyanobacterial coverage was higher in Mjimwema (31–100%) than in Ocean Road (0–60%). The levels of nutrients in tidal pool waters at Ocean Road ranged from 0.45–1.03 μmol NO3 -N/l, 0.19–0.27 μmol NO2 -N/l and 0.03–0.09 μmol PO4 ...

Nonstimulated human uncommitted mesenchymal stem cells express cell markers of mesenchymal and neural lineages.

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Minguell, José J; Fierro, Fernando A; Epuñan, María J; Erices, Alejandro A; Sierralta, Walter D

2005-08-01

Ex vivo cultures of human bone marrow-derived mesenchymal stem cells (MSCs) contain subsets of progenitors exhibiting dissimilar properties. One of these subsets comprises uncommitted progenitors displaying distinctive features, such as morphology, a quiescent condition, growth factor production, and restricted tissue biodistribution after transplantation. In this study, we assessed the competence of these cells to express, in the absence of differentiation stimuli, markers of mesoderm and ectodermic (neural) cell lineages. Fluorescence microscopy analysis showed a unique pattern of expression of osteogenic, chondrogenic, muscle, and neural markers. The depicted "molecular signature" of these early uncommitted progenitors, in the absence of differentiation stimuli, is consistent with their multipotentiality and plasticity as suggested by several in vitro and in vivo studies.

Acute leukemias of ambiguous lineage.

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Béné, Marie C; Porwit, Anna

2012-02-01

The 2008 edition of the WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues recognizes a special category called "leukemias of ambiguous lineage." The vast majority of these rare leukemias are classified as mixed phenotype acute leukemia (MPAL), although acute undifferentiated leukemias and natural killer lymphoblastic leukemias are also included. The major immunophenotypic markers used by the WHO 2008 to determine the lineage for these proliferations are myeloperoxidase, CD19, and cytoplasmic CD3. However, extensive immunophenotyping is necessary to confirm that the cells indeed belong to 2 different lineages or coexpress differentiation antigens of more than 1 lineage. Specific subsets of MPAL are defined by chromosomal anomalies such as the t(9;22) Philadelphia chromosome BCR-ABL1 or involvement of the MLL gene on chromosome 11q23. Other MPAL are divided into B/myeloid NOS, T/myeloid NOS, B/T NOS, and B/T/myeloid NOS. MPAL are usually of dire prognosis, respond variably to chemotherapy of acute lymphoblastic or acute myeloblastic type, and benefit most from rapid allogeneic hematopoietic stem cell transplantation.

Cytokine-Regulated GADD45G Induces Differentiation and Lineage Selection in Hematopoietic Stem Cells

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Frederic B. Thalheimer

2014-07-01

Full Text Available The balance of self-renewal and differentiation in long-term repopulating hematopoietic stem cells (LT-HSC must be strictly controlled to maintain blood homeostasis and to prevent leukemogenesis. Hematopoietic cytokines can induce differentiation in LT-HSCs; however, the molecular mechanism orchestrating this delicate balance requires further elucidation. We identified the tumor suppressor GADD45G as an instructor of LT-HSC differentiation under the control of differentiation-promoting cytokine receptor signaling. GADD45G immediately induces and accelerates differentiation in LT-HSCs and overrides the self-renewal program by specifically activating MAP3K4-mediated MAPK p38. Conversely, the absence of GADD45G enhances the self-renewal potential of LT-HSCs. Videomicroscopy-based tracking of single LT-HSCs revealed that, once GADD45G is expressed, the development of LT-HSCs into lineage-committed progeny occurred within 36 hr and uncovered a selective lineage choice with a severe reduction in megakaryocytic-erythroid cells. Here, we report an unrecognized role of GADD45G as a central molecular linker of extrinsic cytokine differentiation and lineage choice control in hematopoiesis.

Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds.

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Song, Min Jae; Dean, David; Knothe Tate, Melissa L

2013-07-01

Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to "map the mechanome", defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cyanobacterial crust induction using two non-previously tested cyanobacterial inoculants: crusting capability and role of EPSs

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Mugnai, Gianmarco; Rossi, Federico; De Philippis, Roberto

2017-04-01

The use of cyanobacteria as soil improvers and bio-conditioners (a technique often referred to as algalization) has been studied for decades. Several studies proved that cyanobacteria are feasible eco-friendly candidates to trigger soil fertilization and enrichment from agricultural to arid and hyper-arid systems. This approach can be successful to achieve stabilization and rehabilitation of degraded environments. Much of the effectiveness of algalization is due to the productivity and the characteristics of extracellular polysaccharides (EPSs) which, among their features, embed soil particles and promote the development of a first stable organo-mineral layer (cyanobacterial crusts). In natural settings, cyanobacterial crust induction represents a first step of a succession that may lead to the formation of mature biological soil crusts (Lan et al., 2014). The aim of this research was to investigate the crusting capabilities, and the characteristics of excreted EPSs by two newly tested non-heterocystous cyanobacterial inoculants, in microcosm experiments carried out using oligothrophic sand collected from sand dunes in Negev Desert, Israel. The cyanobacteria tested were Schizothrix AMPL1601, originally isolated from biocrusts collected in Hobq Desert, Inner Mongolia (China) and Leptolyngbia ohadii, originally isolated from biocrusts collected in Negev Desert, Israel. Inoculated microcosms were maintained at 30 °C in a growth chamber under continuous illumination and minimal water availability. Under such stressing conditions, and for a three-months incubation time, the growth and the colonization of the strains in the microcosms were monitored. At the same time, EPSs production and their chemical and macromolecular characteristics were determined by applying a methodology optimized for the purpose. Notably, EPSs were analyzed in two operationally-defined fractions, one more dispersed in the crust matrix (loosely bound EPSs, LB-EPSs) and one more condensed and

Cell lineage specific distribution of H3K27 trimethylation accumulation in an in vitro model for human implantation.

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Gijs Teklenburg

Full Text Available Female mammals inactivate one of their two X-chromosomes to compensate for the difference in gene-dosage with males that have just one X-chromosome. X-chromosome inactivation is initiated by the expression of the non-coding RNA Xist, which coats the X-chromosome in cis and triggers gene silencing. In early mouse development the paternal X-chromosome is initially inactivated in all cells of cleavage stage embryos (imprinted X-inactivation followed by reactivation of the inactivated paternal X-chromosome exclusively in the epiblast precursors of blastocysts, resulting temporarily in the presence of two active X-chromosomes in this specific lineage. Shortly thereafter, epiblast cells randomly inactivate either the maternal or the paternal X-chromosome. XCI is accompanied by the accumulation of histone 3 lysine 27 trimethylation (H3K27me3 marks on the condensed X-chromosome. It is still poorly understood how XCI is regulated during early human development. Here we have investigated lineage development and the distribution of H3K27me3 foci in human embryos derived from an in-vitro model for human implantation. In this system, embryos are co-cultured on decidualized endometrial stromal cells up to day 8, which allows the culture period to be extended for an additional two days. We demonstrate that after the co-culture period, the inner cell masses have relatively high cell numbers and that the GATA4-positive hypoblast lineage and OCT4-positive epiblast cell lineage in these embryos have segregated. H3K27me3 foci were observed in ∼25% of the trophectoderm cells and in ∼7.5% of the hypoblast cells, but not in epiblast cells. In contrast with day 8 embryos derived from the co-cultures, foci of H3K27me3 were not observed in embryos at day 5 of development derived from regular IVF-cultures. These findings indicate that the dynamics of H3K27me3 accumulation on the X-chromosome in human development is regulated in a lineage specific fashion.

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages

International Nuclear Information System (INIS)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J.; Fernandez, Anne

2008-01-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal β III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages.

Science.gov (United States)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J; Fernandez, Anne

2008-04-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal beta III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders.

Determining Lineage Pathways from Cellular Barcoding Experiments

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Leïla Perié

2014-02-01

Full Text Available Cellular barcoding and other single-cell lineage-tracing strategies form experimental methodologies for analysis of in vivo cell fate that have been instrumental in several significant recent discoveries. Due to the highly nonlinear nature of proliferation and differentiation, interrogation of the resulting data for evaluation of potential lineage pathways requires a new quantitative framework complete with appropriate statistical tests. Here, we develop such a framework, illustrating its utility by analyzing data from barcoded multipotent cells of the blood system. This application demonstrates that the data require additional paths beyond those found in the classical model, which leads us to propose that hematopoietic differentiation follows a loss of potential mechanism and to suggest further experiments to test this deduction. Our quantitative framework can evaluate the compatibility of lineage trees with barcoded data from any proliferating and differentiating cell system.

Lineage-specific function of Engrailed-2 in the progression of chronic myelogenous leukemia to T-cell blast crisis.

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Abollo-Jiménez, Fernando; Campos-Sánchez, Elena; Toboso-Navasa, Amparo; Vicente-Dueñas, Carolina; González-Herrero, Inés; Alonso-Escudero, Esther; González, Marcos; Segura, Víctor; Blanco, Oscar; Martínez-Climent, José Angel; Sánchez-García, Isidro; Cobaleda, César

2014-01-01

In hematopoietic malignancies, oncogenic alterations interfere with cellular differentiation and lead to tumoral development. Identification of the proteins regulating differentiation is essential to understand how they are altered in malignancies. Chronic myelogenous leukemia (CML) is a biphasic disease initiated by an alteration taking place in hematopoietic stem cells. CML progresses to a blast crisis (BC) due to a secondary differentiation block in any of the hematopoietic lineages. However, the molecular mechanisms of CML evolution to T-cell BC remain unclear. Here, we have profiled the changes in DNA methylation patterns in human samples from BC-CML, in order to identify genes whose expression is epigenetically silenced during progression to T-cell lineage-specific BC. We have found that the CpG-island of the ENGRAILED-2 (EN2) gene becomes methylated in this progression. Afterwards, we demonstrate that En2 is expressed during T-cell development in mice and humans. Finally, we further show that genetic deletion of En2 in a CML transgenic mouse model induces a T-cell lineage BC that recapitulates human disease. These results identify En2 as a new regulator of T-cell differentiation whose disruption induces a malignant T-cell fate in CML progression, and validate the strategy used to identify new developmental regulators of hematopoiesis.

Bioenergetic Changes during Differentiation of Human Embryonic Stem Cells along the Hepatic Lineage

DEFF Research Database (Denmark)

Hopkinson, Branden M; Madsen, Claus Desler; Kalisz, Mark

2017-01-01

Mitochondrial dysfunction has been demonstrated to result in premature aging due to its effects on stem cells. Nevertheless, a full understanding of the role of mitochondrial bioenergetics through differentiation is still lacking. Here we show the bioenergetics profile of human stem cells...... of embryonic origin differentiating along the hepatic lineage. Our study reveals especially the transition between hepatic specification and hepatic maturation as dependent on mitochondrial respiration and demonstrates that even though differentiating cells are primarily dependent on glycolysis until induction...

Stability of Control Networks in Autonomous Homeostatic Regulation of Stem Cell Lineages.

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Komarova, Natalia L; van den Driessche, P

2018-05-01

Design principles of biological networks have been studied extensively in the context of protein-protein interaction networks, metabolic networks, and regulatory (transcriptional) networks. Here we consider regulation networks that occur on larger scales, namely the cell-to-cell signaling networks that connect groups of cells in multicellular organisms. These are the feedback loops that orchestrate the complex dynamics of cell fate decisions and are necessary for the maintenance of homeostasis in stem cell lineages. We focus on "minimal" networks that are those that have the smallest possible numbers of controls. For such minimal networks, the number of controls must be equal to the number of compartments, and the reducibility/irreducibility of the network (whether or not it can be split into smaller independent sub-networks) is defined by a matrix comprised of the cell number increments induced by each of the controlled processes in each of the compartments. Using the formalism of digraphs, we show that in two-compartment lineages, reducible systems must contain two 1-cycles, and irreducible systems one 1-cycle and one 2-cycle; stability follows from the signs of the controls and does not require magnitude restrictions. In three-compartment systems, irreducible digraphs have a tree structure or have one 3-cycle and at least two more shorter cycles, at least one of which is a 1-cycle. With further work and proper biological validation, our results may serve as a first step toward an understanding of ways in which these networks become dysregulated in cancer.

Cyanobacterial bloom in the world largest freshwater lake Baikal

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Namsaraev, Zorigto; Melnikova, Anna; Ivanov, Vasiliy; Komova, Anastasia; Teslyuk, Anton

2018-02-01

Lake Baikal is a UNESCO World Heritage Site and holds 20% of the world’s freshwater reserves. On July 26, 2016, a cyanobacterial bloom of a green colour a few kilometers in size with a bad odor was discovered by local people in the Barguzinsky Bay on the eastern shore of Lake Baikal. Our study showed very high concentration of chlorophyll a (41.7 g/m3) in the sample of bloom. We found that the bloom was dominated by a nitrogen-fixing heterocystous cyanobacteria of the genus Dolichospermum. The mass accumulation of cyanobacteria in the lake water with an extremely high chlorophyll a concentration can be explained by a combination of several factors: the discharge of biologicaly-available nutrients, including phosphorus, into the water of Lake Baikal; low wind speed and weak water mixing; buoyant cyanobacterial cells on the lake surface, which drifted towards the eastern coast, where the maximum concentration of chlorophyll a was recorded. In the center of the Barguzinsky Bay and in the open part of Lake Baikal, according to satellite data, the chlorophyll a concentration is several orders of magnitude lower than at the shoreline.

Molecular Diffusion through Cyanobacterial Septal Junctions

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Mercedes Nieves-Morión

2017-01-01

Full Text Available Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N2-fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the “septal junctions” (formerly known as “microplasmodesmata” linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans.

The current status of cyanobacterial nomenclature under the "prokaryotic" and the "botanical" code.

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Oren, Aharon; Ventura, Stefano

2017-10-01

Cyanobacterial taxonomy developed in the botanical world because Cyanobacteria/Cyanophyta have traditionally been identified as algae. However, they possess a prokaryotic cell structure, and phylogenetically they belong to the Bacteria. This caused nomenclature problems as the provisions of the International Code of Nomenclature for algae, fungi, and plants (ICN; the "Botanical Code") differ from those of the International Code of Nomenclature of Prokaryotes (ICNP; the "Prokaryotic Code"). While the ICN recognises names validly published under the ICNP, Article 45(1) of the ICN has not yet been reciprocated in the ICNP. Different solutions have been proposed to solve the current problems. In 2012 a Special Committee on the harmonisation of the nomenclature of Cyanobacteria was appointed, but its activity has been minimal. Two opposing proposals to regulate cyanobacterial nomenclature were recently submitted, one calling for deletion of the cyanobacteria from the groups of organisms whose nomenclature is regulated by the ICNP, the second to consistently apply the rules of the ICNP to all cyanobacteria. Following a general overview of the current status of cyanobacterial nomenclature under the two codes we present five case studies of genera for which nomenclatural aspects have been discussed in recent years: Microcystis, Planktothrix, Halothece, Gloeobacter and Nostoc.

Epiblast cells that express MyoD recruit pluripotent cells to the skeletal muscle lineage

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Gerhart, Jacquelyn; Neely, Christine; Stewart, Benjamin; Perlman, Jordanna; Beckmann, David; Wallon, Margaretha; Knudsen, Karen; George-Weinstein, Mindy

2004-01-01

Embryonic stem cells are derived from the epiblast. A subpopulation of epiblast cells expresses MyoD mRNA and the G8 antigen in vivo. G8 positive (G8pos) and G8 negative (G8neg) populations were isolated by magnetic cell sorting. Nearly all G8pos cells switched from E- to N-cadherin and differentiated into skeletal muscle in culture. G8neg cells were impaired in their ability to switch cadherins and few formed skeletal muscle. Medium conditioned by G8pos cells stimulated skeletal myogenesis and N-cadherin synthesis in G8neg cultures. The effect of conditioned medium from G8pos cultures was inhibited by bone morphogenetic protein (BMP) 4. Treatment of G8neg cells with a soluble form of the BMP receptor-IA or Noggin promoted N-cadherin synthesis and skeletal myogenesis. These results demonstrate that MyoD-positive epiblast cells recruit pluripotent cells to the skeletal muscle lineage. The mechanism of recruitment involves blocking the BMP signaling pathway. PMID:14981095

Leu-9 (CD 7) positivity in acute leukemias: a marker of T-cell lineage?

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Ben-Ezra, J; Winberg, C D; Wu, A; Rappaport, H

1987-01-01

Monoclonal antibody Leu-9 (CD 7) has been reported to be a sensitive and specific marker for T-cell lineage in leukemic processes, since it is positive in patients whose leukemic cells fail to express other T-cell antigens. To test whether Leu-9 is indeed specific for T-cell leukemias, we examined in detail 10 cases of acute leukemia in which reactions were positive for Leu-9 and negative for other T-cell-associated markers including T-11, Leu-1, T-3, and E-rosettes. Morphologically and cytochemically, 2 of these 10 leukemias were classified as lymphoblastic, 4 as myeloblastic, 2 as monoblastic, 1 as megakaryoblastic, and 1 as undifferentiated. The case of acute megakaryoblastic leukemia is the first reported case to be Leu-9 positive. None of the 10 were TdT positive. Of six cases (two monoblastic, one lymphoblastic, one myeloblastic, one megakaryoblastic, and one undifferentiated) in which we evaluated for DNA gene rearrangements, only one, a peroxidase-positive leukemia, showed a novel band on study of the T-cell-receptor beta-chain gene. We therefore conclude that Leu-9 is not a specific marker to T-cell lineage and that, in the absence of other supporting data, Leu-9 positivity should not be used as the sole basis of classifying an acute leukemia as being T-cell derived.

Imaging retinal progenitor lineages in developing zebrafish embryos.

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Jusuf, Patricia; Harris, William A; Poggi, Lucia

2013-03-01

In this protocol, we describe how to make and analyze four dimensional (4D) movies of retinal lineage in the zebrafish embryo in vivo. 4D consists of three spatial dimensions (3D) reconstructed from stacks of confocal planes plus one time dimension. Our imaging is performed on transgenic cells that express fluorescent proteins under the control of cell-specific promoters or on cells that transiently express such reporters in specific retinal cell progenitors. An important aspect of lineage tracing is the ability to follow individual cells as they undergo multiple cell divisions, final migration, and differentiation. This may mean many hours of 4D imaging, requiring that cells be kept healthy and maintained under conditions suitable for normal development. The longest movies we have made are ∼50 h. By analyzing these movies, we can see when a specific cell was born and who its sister was, allowing us to reconstruct its retinal lineages in vivo.

Zika Virus Exhibits Lineage-Specific Phenotypes in Cell Culture, in Aedes aegypti Mosquitoes, and in an Embryo Model

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Katherine A. Willard

2017-12-01

Full Text Available Zika virus (ZIKV has quietly circulated in Africa and Southeast Asia for the past 65 years. However, the recent ZIKV epidemic in the Americas propelled this mosquito-borne virus to the forefront of flavivirus research. Based on historical evidence, ZIKV infections in Africa were sporadic and caused mild symptoms such as fever, skin rash, and general malaise. In contrast, recent Asian-lineage ZIKV infections in the Pacific Islands and the Americas are linked to birth defects and neurological disorders. The aim of this study is to compare replication, pathogenicity, and transmission efficiency of two historic and two contemporary ZIKV isolates in cell culture, the mosquito host, and an embryo model to determine if genetic variation between the African and Asian lineages results in phenotypic differences. While all tested isolates replicated at similar rates in Vero cells, the African isolates displayed more rapid viral replication in the mosquito C6/36 cell line, yet they exhibited poor infection rates in Aedes aegypti mosquitoes compared to the contemporary Asian-lineage isolates. All isolates could infect chicken embryos; however, infection with African isolates resulted in higher embryo mortality than infection with Asian-lineage isolates. These results suggest that genetic variation between ZIKV isolates can significantly alter experimental outcomes.

Clonal reversal of ageing-associated stem cell lineage bias via a pluripotent intermediate

DEFF Research Database (Denmark)

Wahlestedt, Martin; Erlandsson, Eva; Kristiansen, Trine

2017-01-01

Ageing associates with significant alterations in somatic/adult stem cells and therapies to counteract these might have profound benefits for health. In the blood, haematopoietic stem cell (HSC) ageing is linked to several functional shortcomings. However, besides the recent realization...... with the generation of induced pluripotent stem (iPS) cells. This allows us to specifically focus on aged HSCs presenting with a pronounced lineage skewing, a hallmark of HSC ageing. Functional and molecular evaluations reveal haematopoiesis from these iPS clones to be indistinguishable from that associating...

At the crossroads of fate - somatic cell lineage specification in the fetal gonad

DEFF Research Database (Denmark)

Rotgers, Emmi; Jørgensen, Anne; Yao, Humphrey Hung-Chang

2018-01-01

The reproductive endocrine systems are vastly different between male and female. This sexual dimorphism of endocrine milieu originates from sex-specific differentiation of the somatic cells in the gonads during fetal life. The majority of gonadal somatic cells arise from the adrenogonadal...... of the reproductive tracts. Impairment of lineage specification and function of gonadal somatic cells can lead to disorders of sexual development (DSDs) in humans. Human DSDs and processes for gonadal development have been successfully modelled using genetically modified mouse models. In this review, we focus...

Cell lineage identification and stem cell culture in a porcine model for the study of intestinal epithelial regeneration.

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Liara M Gonzalez

Full Text Available Significant advances in intestinal stem cell biology have been made in murine models; however, anatomical and physiological differences between mice and humans limit mice as a translational model for stem cell based research. The pig has been an effective translational model, and represents a candidate species to study intestinal epithelial stem cell (IESC driven regeneration. The lack of validated reagents and epithelial culture methods is an obstacle to investigating IESC driven regeneration in a pig model. In this study, antibodies against Epithelial Adhesion Molecule 1 (EpCAM and Villin marked cells of epithelial origin. Antibodies against Proliferative Cell Nuclear Antigen (PCNA, Minichromosome Maintenance Complex 2 (MCM2, Bromodeoxyuridine (BrdU and phosphorylated Histone H3 (pH3 distinguished proliferating cells at various stages of the cell cycle. SOX9, localized to the stem/progenitor cells zone, while HOPX was restricted to the +4/'reserve' stem cell zone. Immunostaining also identified major differentiated lineages. Goblet cells were identified by Mucin 2 (MUC2; enteroendocrine cells by Chromogranin A (CGA, Gastrin and Somatostatin; and absorptive enterocytes by carbonic anhydrase II (CAII and sucrase isomaltase (SIM. Transmission electron microscopy demonstrated morphologic and sub-cellular characteristics of stem cell and differentiated intestinal epithelial cell types. Quantitative PCR gene expression analysis enabled identification of stem/progenitor cells, post mitotic cell lineages, and important growth and differentiation pathways. Additionally, a method for long-term culture of porcine crypts was developed. Biomarker characterization and development of IESC culture in the porcine model represents a foundation for translational studies of IESC-driven regeneration of the intestinal epithelium in physiology and disease.

Transcriptional regulation of lineage commitment--a stochastic model of cell fate decisions.

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Jose Teles

Full Text Available Molecular mechanisms employed by individual multipotent cells at the point of lineage commitment remain largely uncharacterized. Current paradigms span from instructive to noise-driven mechanisms. Of considerable interest is also whether commitment involves a limited set of genes or the entire transcriptional program, and to what extent gene expression configures multiple trajectories into commitment. Importantly, the transient nature of the commitment transition confounds the experimental capture of committing cells. We develop a computational framework that simulates stochastic commitment events, and affords mechanistic exploration of the fate transition. We use a combined modeling approach guided by gene expression classifier methods that infers a time-series of stochastic commitment events from experimental growth characteristics and gene expression profiling of individual hematopoietic cells captured immediately before and after commitment. We define putative regulators of commitment and probabilistic rules of transition through machine learning methods, and employ clustering and correlation analyses to interrogate gene regulatory interactions in multipotent cells. Against this background, we develop a Monte Carlo time-series stochastic model of transcription where the parameters governing promoter status, mRNA production and mRNA decay in multipotent cells are fitted to experimental static gene expression distributions. Monte Carlo time is converted to physical time using cell culture kinetic data. Probability of commitment in time is a function of gene expression as defined by a logistic regression model obtained from experimental single-cell expression data. Our approach should be applicable to similar differentiating systems where single cell data is available. Within our system, we identify robust model solutions for the multipotent population within physiologically reasonable values and explore model predictions with regard to

Does cell lineage in the developing cerebral cortex contribute to its columnar organization?

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Marcos R Costa

2010-06-01

Full Text Available Since the pioneer work of Lorente de Nó, Ramón y Cajal, Brodmann, Mountcastle, Hubel and Wiesel and others, the cerebral cortex has been seen as a jigsaw of anatomic and functional modules involved in the processing of different sets of information. In fact, a columnar distribution of neurons displaying similar functional properties throughout the cerebral cortex has been observed by many researchers. Although it has been suggested that much of the anatomical substrate for such organization would be already specified at early developmental stages, before activity-dependent mechanisms could take place, it is still unclear whether gene expression in the ventricular zone could play a role in the development of discrete functional units, such as minicolumns or columns. Cell lineage experiments using replication-incompetent retroviral vectors have shown that the progeny of a single neuroepithelial/radial glial cell in the dorsal telencephalon is organized into discrete radial clusters of sibling excitatory neurons, which have a higher propensity for developing chemical synapses with each other rather than with neighbouring non-siblings. Here, we will discuss the possibility that the cell lineage of single neuroepithelial/radial glia cells could contribute for the columnar organization of the neocortex by generating radial columns of sibling, interconnected neurons. Borrowing some concepts from the studies on cell-cell recognition and transcription factor networks, we will also touch upon the potential molecular mechanisms involved in the establishment of sibling-neuron circuits.

Cell lineage patterns in the shoot meristem of the sunflower embryo in the dry seed

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Jegla, D.E.; Sussex, I.M.

1989-01-01

We mapped the fate of cells in the shoot meristem of the dry-seed embryo of sunflower, Helianthus annuus L. cv. Peredovic, using irradiation-induced somatic sectors. We analyzed 249 chlorophyll-deficient or glabrous (hairless) sectors generated in 236 plants. Most sectors observed in the inflorescence extended into vegetative nodes. Thus cell lineages that ultimately gave rise to reproductive structures also contributed to vegetative structures. No single sector extended the entire length of the shoot. Thus the shoot is not derived from one or a few apical initials. Rather, the position, vertical extent, and width of the sectors at different levels of the shoot suggest that the shoot is derived from three to four circumferential populations of cells in each of three cell layers of the embryo meristem. Sectors had no common boundaries even in plants with two or three independent sectors, but varied in extent and overlapped along the length of the shoot. Thus individual cells in a single circumferential population behaved independently to contribute lineages of different vertical extents to the growing shoot. The predicted number of circumferential populations of cells as well as the apparent cell number in each population was consistent with the actual number of cells in the embryo meristem observed in histological sections

Cyanobacterial Farming for Environment Friendly Sustainable Agriculture Practices: Innovations and Perspectives

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Jainendra Pathak

2018-02-01

Full Text Available Sustainable supply of food and energy without posing any threat to environment is the current demand of our society in view of continuous increase in global human population and depletion of natural resources of energy. Cyanobacteria have recently emerged as potential candidates who can fulfill abovementioned needs due to their ability to efficiently harvest solar energy and convert it into biomass by simple utilization of CO2, water and nutrients. During conversion of radiant energy into chemical energy, these biological systems produce oxygen as a by-product. Cyanobacterial biomass can be used for the production of food, energy, biofertilizers, secondary metabolites of nutritional, cosmetics, and medicinal importance. Therefore, cyanobacterial farming is proposed as environment friendly sustainable agricultural practice which can produce biomass of very high value. Additionally, cyanobacterial farming helps in decreasing the level of greenhouse gas, i.e., CO2, and it can be also used for removing various contaminants from wastewater and soil. However, utilization of cyanobacteria for resolving the abovementioned problems is subjected to economic viability. In this review, we provide details on different aspects of cyanobacterial system that can help in developing sustainable agricultural practices. We also describe different large-scale cultivation systems for cyanobacterial farming and discuss their merits and demerits in terms of economic profitability.

Hematopoietic microenvironment. Origin, lineage, and transplantability of the stromal cells in long-term bone marrow cultures from chimeric mice

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Perkins, S.; Fleischman, R.A.

1988-01-01

Studies of bone marrow transplant patients have suggested that the stromal cells of the in vitro hematopoietic microenvironment are transplantable into conditioned recipients. Moreover, in patients with myeloproliferative disorders, all of the stromal cells, which include presumptive endothelial cells, appear to be derived from hematopoietic precursors. To confirm these findings, we have constructed two chimeric mouse models: (a) traditional radiation chimeras, and (b) fetal chimeras, produced by placental injection of bone marrow into genetically anemic Wx/Wv fetuses, a technique that essentially precludes engraftment of nonhematopoietic cells. Using two-color indirect immunofluorescence, the stromal cells in long-term bone marrow culture derived from these chimeras were analyzed for donor or host origin by strain-specific H-2 antigens, and for cell lineage by a variety of other specific markers. 75-95% of the stromal cells were shown to be hematopoietic cells of the monocyte-macrophage lineage, based upon donor origin, phagocytosis, and expression of specific hematopoietic surface antigens. The remaining 5-25% of the stromal cells were exclusively host in origin. Apart from occasional fat cells, these cells uniformly expressed collagen type IV, laminin, and a surface antigen associated with endothelial cells. Since these endothelial-like cells are not transplantable into radiation or fetal chimeras, they are not derived from hematopoietic stem cells. The contrast between our findings and human studies suggests either unexpected species differences in the origin of stromal lineages or limitations in the previous methodology used to detect nonhematopoietic stromal cells

Phosphonate degradation by Spirulina strains: cyanobacterial biofilters for the removal of anticorrosive polyphosphonates from wastewater.

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Forlani, Giuseppe; Prearo, Valentina; Wieczorek, Dorota; Kafarski, Paweł; Lipok, Jacek

2011-03-07

The ability of Spirulina spp. to metabolize the recalcitrant xenobiotic Dequest 2054(®) [hexamethylenediamine-N,N,N',N'-tetrakis(methylphosphonic acid)], a CaSO(4) inhibitor used for boiler treatment and reverse osmosis desalination, was investigated. The compound served as sole source of phosphorus, but not of nitrogen, for cyanobacterial growth. In vivo utilization was followed by (31)P NMR analysis. The disappearance of the polyphosphonate proceeded only with actively dividing cells, and no release of inorganic phosphate was evident. However, no difference was found between P-starved and P-fed cultures. Maximal utilization reached 1.0 ± 0.2 mmoll(-1), corresponding to 0.56 ± 0.11 mmol g(-1) dry biomass, thus residual amounts were still present in the exhausted medium when the compound was supplied at higher initial concentrations. At low substrate levels metabolism rates were lower, suggesting that a concentration-driven uptake may represent a limiting step during the biodegradation process. The compound was not retained by biocolumns made with immobilized cyanobacterial cells, either alive or dead. A lab-scale pilot plant, consisting of a series of sequentially connected vessels containing an actively proliferating algal culture, was built and tested for wastewater treatment. Results showed 50% removal of the polyphosphonate added to an initial concentration of 2.5mM. Although further optimization will be required, data strengthen the possibility of using cyanobacterial strains for bioremediation purposes. Copyright © 2010 Elsevier Inc. All rights reserved.

Limiting dilution analysis of the stem cells for T cell lineage

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Katsura, Y.; Kina, T.; Amagai, T.; Tsubata, T.; Hirayoshi, K.; Takaoki, Y.; Sado, T.; Nishikawa, S.I.

1986-01-01

Stem cell activities of bone marrow, spleen, thymus, and fetal liver cells for T cell lineage were studied comparatively by transferring the cells from these organs through i.v. or intrathymus (i.t.) route into right leg- and tail-shielded (L-T-shielded) and 900 R-irradiated recipient mice, which were able to survive without supplying hemopoietic stem cells. Cells from B10.Thy-1.1 (H-2b, Thy-1.1) mice were serially diluted and were transferred into L-T-shielded and irradiated C57BL/6 (H-2b, Thy-1.2) mice, and 21 days later the thymus cells of recipient mice were assayed for Thy-1.1+ cells by flow cytofluorometry. The percentage of recipient mice possessing donor-type T cells was plotted against the number of cells transferred, and the stem cell activity in each cell source was expressed as the 50% positive value, the number of donor cells required for generating donor-type T cells in the thymuses of 50% of recipient mice. In i.v. transfer experiments, the activity of bone marrow cells was similar to that of fetal liver cells, and about 100 times and nearly 1000 times higher than those of spleen cells and thymus cells, respectively. In i.t. transfer experiments, the number of cells required for generating donor-type T cells was much lower than that in i.v. transfer experiments, although the ratio in 50% positive values between i.v. and i.t. transfers differed among cell sources. In i.t. transfers, the 50% positive value of bone marrow cells was five times, 400 times, and 500 times higher than that of fetal liver cells, spleen cells, and thymus cells, respectively. Our previous finding that stem cells are enriched in the spleens of mice which were whole body-irradiated and marrow-reconstituted 7 days earlier was confirmed also by the present limiting dilution assay carried out in i.v. as well as i.t. transfers

Quantitative iTRAQ LC-MS/MS proteomics reveals metabolic responses to biofuel ethanol in cyanobacterial Synechocystis sp. PCC 6803.

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Qiao, Jianjun; Wang, Jiangxin; Chen, Lei; Tian, Xiaoxu; Huang, Siqiang; Ren, Xiaoyue; Zhang, Weiwen

2012-11-02

Recent progress in metabolic engineering has led to autotrophic production of ethanol in various cyanobacterial hosts. However, cyanobacteria are known to be sensitive to ethanol, which restricts further efforts to increase ethanol production levels in these renewable host systems. To understand the mechanisms of ethanol tolerance so that engineering more robust cyanobacterial hosts can be possible, in this study, the responses of model cyanobacterial Synechocystis sp. PCC 6803 to ethanol were determined using a quantitative proteomics approach with iTRAQ LC-MS/MS technologies. The resulting high-quality proteomic data set consisted of 24,887 unique peptides corresponding to 1509 identified proteins, a coverage of approximately 42% of the predicted proteins in the Synechocystis genome. Using a cutoff of 1.5-fold change and a p-value less than 0.05, 135 and 293 unique proteins with differential abundance levels were identified between control and ethanol-treated samples at 24 and 48 h, respectively. Functional analysis showed that the Synechocystis cells employed a combination of induced common stress response, modifications of cell membrane and envelope, and induction of multiple transporters and cell mobility-related proteins as protection mechanisms against ethanol toxicity. Interestingly, our proteomic analysis revealed that proteins related to multiple aspects of photosynthesis were up-regulated in the ethanol-treated Synechocystis cells, consistent with increased chlorophyll a concentration in the cells upon ethanol exposure. The study provided the first comprehensive view of the complicated molecular mechanisms against ethanol stress and also provided a list of potential gene targets for further engineering ethanol tolerance in Synechocystis PCC 6803.

Differentiation of retinal ganglion cells and photoreceptor precursors from mouse induced pluripotent stem cells carrying an Atoh7/Math5 lineage reporter.

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Bin-Bin Xie

Full Text Available The neural retina is a critical component of the visual system, which provides the majority of sensory input in humans. Various retinal degenerative diseases can result in the permanent loss of retinal neurons, especially the light-sensing photoreceptors and the centrally projecting retinal ganglion cells (RGCs. The replenishment of lost RGCs and the repair of optic nerve damage are particularly challenging, as both RGC specification and their subsequent axonal growth and projection involve complex and precise regulation. To explore the developmental potential of pluripotent stem cell-derived neural progenitors, we have established mouse iPS cells that allow cell lineage tracing of progenitors that have expressed Atoh7/Math5, a bHLH transcription factor required for RGC production. These Atoh7 lineage reporter iPS cells encode Cre to replace one copy of the endogenous Atoh7 gene and a Cre-dependent YFP reporter in the ROSA locus. In addition, they express pluripotent markers and are capable of generating teratomas in vivo. Under anterior neural induction and neurogenic conditions in vitro, the Atoh7-Cre/ROSA-YFP iPS cells differentiate into neurons that co-express various RGC markers and YFP, indicating that these neurons are derived from Atoh7-expressing progenitors. Consistent with previous in vivo cell lineage studies, the Atoh7-Cre/ROSA-YFP iPS cells also give rise to a subset of Crx-positive photoreceptor precursors. Furthermore, inhibition of Notch signaling in the iPSC cultures results in a significant increase of YFP-positive RGCs and photoreceptor precursors. Together, these results show that Atoh7-Cre/ROSA-YFP iPS cells can be used to monitor the development and survival of RGCs and photoreceptors from pluripotent stem cells.

Epigenetic Reprogramming of Lineage-Committed Human Mammary Epithelial Cells Requires DNMT3A and Loss of DOT1L

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Jerrica L. Breindel

2017-09-01

Full Text Available Organogenesis and tissue development occur through sequential stepwise processes leading to increased lineage restriction and loss of pluripotency. An exception to this appears in the adult human breast, where rare variant epithelial cells exhibit pluripotency and multilineage differentiation potential when removed from the signals of their native microenvironment. This phenomenon provides a unique opportunity to study mechanisms that lead to cellular reprogramming and lineage plasticity in real time. Here, we show that primary human mammary epithelial cells (HMECs lose expression of differentiated mammary epithelial markers in a manner dependent on paracrine factors and epigenetic regulation. Furthermore, we demonstrate that HMEC reprogramming is dependent on gene silencing by the DNA methyltransferase DNMT3A and loss of histone transcriptional marks following downregulation of the methyltransferase DOT1L. These results demonstrate that lineage commitment in adult tissues is context dependent and highlight the plasticity of somatic cells when removed from their native tissue microenvironment.

Changes in glycosaminoglycan structure on differentiation of human embryonic stem cells towards mesoderm and endoderm lineages.

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Gasimli, Leyla; Hickey, Anne Marie; Yang, Bo; Li, Guoyun; dela Rosa, Mitche; Nairn, Alison V; Kulik, Michael J; Dordick, Jonathan S; Moremen, Kelley W; Dalton, Stephen; Linhardt, Robert J

2014-06-01

Proteoglycans are found on the cell surface and in the extracellular matrix, and serve as prime sites for interaction with signaling molecules. Proteoglycans help regulate pathways that control stem cell fate, and therefore represent an excellent tool to manipulate these pathways. Despite their importance, there is a dearth of data linking glycosaminoglycan structure within proteoglycans with stem cell differentiation. Human embryonic stem cell line WA09 (H9) was differentiated into early mesoderm and endoderm lineages, and the glycosaminoglycanomic changes accompanying these transitions were studied using transcript analysis, immunoblotting, immunofluorescence and disaccharide analysis. Pluripotent H9 cell lumican had no glycosaminoglycan chains whereas in splanchnic mesoderm lumican was glycosaminoglycanated. H9 cells have primarily non-sulfated heparan sulfate chains. On differentiation towards splanchnic mesoderm and hepatic lineages N-sulfo group content increases. Differences in transcript expression of NDST1, HS6ST2 and HS6ST3, three heparan sulfate biosynthetic enzymes, within splanchnic mesoderm cells compared to H9 cells correlate to changes in glycosaminoglycan structure. Differentiation of embryonic stem cells markedly changes the proteoglycanome. The glycosaminoglycan biosynthetic pathway is complex and highly regulated, and therefore, understanding the details of this pathway should enable better control with the aim of directing stem cell differentiation. Copyright © 2013 Elsevier B.V. All rights reserved.

Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors

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Maxine A.D. Mowe

2014-12-01

Full Text Available Toxic cyanobacterial blooms are a major issue in freshwater systems in many countries. The potentially toxic species and their ecological causes are likely to be different in tropical zones from those in temperate water bodies; however, studies on tropical toxic cyanobacterial blooms are sporadic and currently there is no global synthesis. In this review, we examined published information on tropical cyanobacterial bloom occurrence and toxin production to investigate patterns in their growth and distribution. Microcystis was the most frequently occurring bloom genus throughout tropical Asia, Africa and Central America, while Cylindrospermopsis and Anabaena blooms occurred in various locations in tropical Australia, America and Africa. Microcystis blooms were more prevalent during the wet season while Cylindrospermopsis blooms were more prevalent during the dry period. Microcystin was the most encountered toxin throughout the tropics. A meta-analysis of tropical cyanobacterial blooms showed that Microcystis blooms were more associated with higher total nitrogen concentrations, while Cylindrospermopsis blooms were more associated with higher maximum temperatures. Meta-analysis also showed a positive linear relationship between levels of microcystin and N:P (nitrate:phosphate ratio. Tropical African Microcystis blooms were found to have the lowest microcystin levels in relation to biomass and N:P (nitrate:phosphate compared to tropical Asian, Australian and American blooms. There was also no significant correlation between microcystin concentration and cell concentration for tropical African blooms as opposed to tropical Asian and American blooms. Our review illustrates that some cyanobacteria and toxins are more prevalent in tropical areas. While some tropical countries have considerable information regarding toxic blooms, others have few or no reported studies. 

Two hemocyte lineages exist in silkworm larval hematopoietic organ.

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Nakahara, Yuichi; Kanamori, Yasushi; Kiuchi, Makoto; Kamimura, Manabu

2010-07-28

Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO) into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

Cyanobacterial Diversity in Biological Soil Crusts along a Precipitation Gradient, Northwest Negev Desert, Israel.

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Hagemann, Martin; Henneberg, Manja; Felde, Vincent J M N L; Drahorad, Sylvie L; Berkowicz, Simon M; Felix-Henningsen, Peter; Kaplan, Aaron

2015-07-01

Cyanobacteria occur worldwide but play an important role in the formation and primary activity of biological soil crusts (BSCs) in arid and semi-arid ecosystems. The cyanobacterial diversity in BSCs of the northwest Negev desert of Israel was surveyed at three fixed sampling stations situated along a precipitation gradient in the years 2010 to 2012. The three stations also are characterized by marked differences in soil features such as soil carbon, nitrogen, or electrical conductivity. The cyanobacterial biodiversity was analyzed by sequencing inserts of clone libraries harboring partial 16S rRNA gene sequences obtained with cyanobacteria-specific primers. Filamentous, non-diazotrophic strains (subsection III), particularly Microcoleus-like, dominated the cyanobacterial community (30% proportion) in all years. Specific cyanobacterial groups showed increased (e.g., Chroococcidiopsis, Leptolyngbya, and Nostoc strains) or decreased (e.g., unicellular strains belonging to the subsection I and Scytonema strains) abundances with declining water availability at the most arid, southern station, whereas many cyanobacterial strains were frequently found in the soils of all three stations. The cyanobacterial diversity at the three sampling stations appears dependent on the available precipitation, whereas the differences in soil chemistry were of lower importance.

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases

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Melissa Crawford

2017-08-01

Full Text Available Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSAmT/mG and Tyr::CreERT2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage.

Cloning from stem cells: different lineages, different species, same story.

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Oback, Björn

2009-01-01

Following nuclear transfer (NT), the most stringent measure of extensive donor cell reprogramming is development into viable offspring. This is referred to as cloning efficiency and quantified as the proportion of cloned embryos transferred into surrogate mothers that survive into adulthood. Cloning efficiency depends on the ability of the enucleated recipient cell to carry out the reprogramming reactions ('reprogramming ability') and the ability of the nuclear donor cell to be reprogrammed ('reprogrammability'). It has been postulated that reprogrammability of the somatic donor cell epigenome is inversely proportional to its differentiation status. In order to test this hypothesis, reprogrammability was compared between undifferentiated stem cells and their differentiated isogenic progeny. In the mouse, cells of divergent differentiation status from the neuronal, haematopoietic and skin epithelial lineage were tested. In cattle and deer, skeletal muscle and antler cells, respectively, were used as donors. No conclusive correlation between differentiation status and cloning efficiency was found, indicating that somatic donor cell type may not be the limiting factor for cloning success. This may reflect technical limitations of the NT-induced reprogramming assay. Alternatively, differentiation status and reprogrammability may be unrelated, making all cells equally difficult to reprogramme once they have left the ground state of pluripotency.

Ecotoxicological effects of selected cyanobacterial secondary metabolites a short review

International Nuclear Information System (INIS)

Wiegand, C.; Pflugmacher, S.

2005-01-01

Cyanobacteria are one of the most diverse groups of gram-negative photosynthetic prokaryotes. Many of them are able to produce a wide range of toxic secondary metabolites. These cyanobacterial toxins can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). Cyanobacterial blooms are hazardous due to this production of secondary metabolites and endotoxins, which could be toxic to animals and plants. Many of the freshwater cyanobacterial blooms include species of the toxigenic genera Microcystis, Anabaena, or Plankthotrix. These compounds differ in mechanisms of uptake, affected organs, and molecular mode of action. In this review, the main focus is the aquatic environment and the effects of these toxins to the organisms living there. Some basic toxic mechanisms will be discussed in comparison to the mammalian system

Pioneer factors govern super-enhancer dynamics in stem cell plasticity and lineage choice

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Adam, Rene C.; Yang, Hanseul; Rockowitz, Shira; Larsen, Samantha B.; Nikolova, Maria; Oristian, Daniel S.; Polak, Lisa; Kadaja, Meelis; Asare, Amma; Zheng, Deyou; Fuchs, Elaine

2015-01-01

Adult stem cells (SCs) reside in niches which balance self-renewal with lineage selection and progression during tissue homeostasis. Following injury, culture or transplantation, SCs outside their niche often display fate flexibility1-4. Here we show that super-enhancers5 underlie the identity, lineage commitment and plasticity of adult SCs in vivo. Using hair follicle (HF) as model, we map the global chromatin domains of HFSCs and their committed progenitors in their native microenvironments. We show that super-enhancers and their dense clusters (‘epicenters’) of transcription factor (TF) binding sites change upon lineage progression. New fate is acquired by decommissioning old and establishing new super-enhancers and/or epicenters, an auto-regulatory process that abates one master regulator subset while enhancing another. We further show that when outside their niche, either in vitro or in wound-repair, HFSCs dynamically remodel super-enhancers in response to changes in their microenvironment. Intriguingly, some key super-enhancers shift epicenters, enabling them to remain active and maintain a transitional state in an ever-changing transcriptional landscape. Finally, we identify SOX9 as a crucial chromatin rheostat of HFSC super-enhancers, and provide functional evidence that super-enhancers are dynamic, dense TF-binding platforms which are acutely sensitive to pioneer master regulators whose levels define not only spatial and temporal features of lineage-status, but also stemness, plasticity in transitional states and differentiation. PMID:25799994

A minimal spatial cell lineage model of epithelium: tissue stratification and multi-stability

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Yeh, Wei-Ting; Chen, Hsuan-Yi

2018-05-01

A minimal model which includes spatial and cell lineage dynamics for stratified epithelia is presented. The dependence of tissue steady state on cell differentiation models, cell proliferation rate, cell differentiation rate, and other parameters are studied numerically and analytically. Our minimal model shows some important features. First, we find that morphogen or mechanical stress mediated interaction is necessary to maintain a healthy stratified epithelium. Furthermore, comparing with tissues in which cell differentiation can take place only during cell division, tissues in which cell division and cell differentiation are decoupled can achieve relatively higher degree of stratification. Finally, our model also shows that in the presence of short-range interactions, it is possible for a tissue to have multiple steady states. The relation between our results and tissue morphogenesis or lesion is discussed.

Concise Review: Plasma and Nuclear Membranes Convey Mechanical Information to Regulate Mesenchymal Stem Cell Lineage.

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Uzer, Gunes; Fuchs, Robyn K; Rubin, Janet; Thompson, William R

2016-06-01

Numerous factors including chemical, hormonal, spatial, and physical cues determine stem cell fate. While the regulation of stem cell differentiation by soluble factors is well-characterized, the role of mechanical force in the determination of lineage fate is just beginning to be understood. Investigation of the role of force on cell function has largely focused on "outside-in" signaling, initiated at the plasma membrane. When interfaced with the extracellular matrix, the cell uses integral membrane proteins, such as those found in focal adhesion complexes to translate force into biochemical signals. Akin to these outside-in connections, the internal cytoskeleton is physically linked to the nucleus, via proteins that span the nuclear membrane. Although structurally and biochemically distinct, these two forms of mechanical coupling influence stem cell lineage fate and, when disrupted, often lead to disease. Here we provide an overview of how mechanical coupling occurs at the plasma and nuclear membranes. We also discuss the role of force on stem cell differentiation, with focus on the biochemical signals generated at the cell membrane and the nucleus, and how those signals influence various diseases. While the interaction of stem cells with their physical environment and how they respond to force is complex, an understanding of the mechanical regulation of these cells is critical in the design of novel therapeutics to combat diseases associated with aging, cancer, and osteoporosis. Stem Cells 2016;34:1455-1463. © 2016 AlphaMed Press.

Exploiting Heparan Sulfate Proteoglycans in Human Neurogenesis—Controlling Lineage Specification and Fate

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Chieh Yu

2017-10-01

Full Text Available Unspecialized, self-renewing stem cells have extraordinary application to regenerative medicine due to their multilineage differentiation potential. Stem cell therapies through replenishing damaged or lost cells in the injured area is an attractive treatment of brain trauma and neurodegenerative neurological disorders. Several stem cell types have neurogenic potential including neural stem cells (NSCs, embryonic stem cells (ESCs, induced pluripotent stem cells (iPSCs, and mesenchymal stem cells (MSCs. Currently, effective use of these cells is limited by our lack of understanding and ability to direct lineage commitment and differentiation of neural lineages. Heparan sulfate proteoglycans (HSPGs are ubiquitous proteins within the stem cell microenvironment or niche and are found localized on the cell surface and in the extracellular matrix (ECM, where they interact with numerous signaling molecules. The glycosaminoglycan (GAG chains carried by HSPGs are heterogeneous carbohydrates comprised of repeating disaccharides with specific sulfation patterns that govern ligand interactions to numerous factors including the fibroblast growth factors (FGFs and wingless-type MMTV integration site family (Wnts. As such, HSPGs are plausible targets for guiding and controlling neural stem cell lineage fate. In this review, we provide an overview of HSPG family members syndecans and glypicans, and perlecan and their role in neurogenesis. We summarize the structural changes and subsequent functional implications of heparan sulfate as cells undergo neural lineage differentiation as well as outline the role of HSPG core protein expression throughout mammalian neural development and their function as cell receptors and co-receptors. Finally, we highlight suitable biomimetic approaches for exploiting the role of HSPGs in mammalian neurogenesis to control and tailor cell differentiation into specific lineages. An improved ability to control stem cell specific neural

Drivers of cyanobacterial diversity and community composition in mangrove soils in south-east Brazil.

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Rigonato, Janaina; Kent, Angela D; Alvarenga, Danillo O; Andreote, Fernando D; Beirigo, Raphael M; Vidal-Torrado, Pablo; Fiore, Marli F

2013-04-01

Cyanobacteria act as primary producers of carbon and nitrogen in nutrient-poor ecosystems such as mangroves. This important group of microorganisms plays a critical role in sustaining the productivity of mangrove ecosystems, but the structure and function of cyanobacteria assemblages can be perturbed by anthropogenic influences. The aim of this work was to assess the community structure and ecological drivers that influence the cyanobacterial community harboured in two Brazilian mangrove soils, and examine the long-term effects of oil contamination on these keystone species. Community fingerprinting results showed that, although cyanobacterial communities are distinct between the two mangroves, the structure and diversity of the assemblages exhibit similar responses to environmental gradients. In each ecosystem, cyanobacteria occupying near-shore areas were similar in composition, indicating importance of marine influences for structuring the community. Analysis of 16S rRNA sequences revealed the presence of diverse cyanobacterial communities in mangrove sediments, with clear differences among mangrove habitats along a transect from shore to forest. While near-shore sites in both mangroves were mainly occupied by Prochlorococcus and Synechococcus genera, sequences retrieved from other mangrove niches were mainly affiliated with uncultured cyanobacterial 16S rRNA. The most intriguing finding was the large number of potentially novel cyanobacteria 16S rRNA sequences obtained from a previously oil-contaminated site. The abundance of cyanobacterial 16S rRNA sequences observed in sites with a history of oil contamination was significantly lower than in the unimpacted areas. This study emphasized the role of environmental drivers in determining the structure of cyanobacterial communities in mangrove soils, and suggests that anthropogenic impacts may also act as ecological filters that select cyanobacterial taxa. These results are an important contribution to our

Toxic Cyanobacterial Bloom Triggers in Missisquoi Bay, Lake Champlain, as Determined by Next-Generation Sequencing and Quantitative PCR

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Nathalie Fortin

2015-05-01

Full Text Available Missisquoi Bay (MB is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages.

Dendritic Cell Lineage Potential in Human Early Hematopoietic Progenitors

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Julie Helft

2017-07-01

Full Text Available Conventional dendritic cells (cDCs are thought to descend from a DC precursor downstream of the common myeloid progenitor (CMP. However, a mouse lymphoid-primed multipotent progenitor has been shown to generate cDCs following a DC-specific developmental pathway independent of monocyte and granulocyte poiesis. Similarly, here we show that, in humans, a large fraction of multipotent lymphoid early progenitors (MLPs gives rise to cDCs, in particular the subset known as cDC1, identified by co-expression of DNGR-1 (CLEC9A and CD141 (BDCA-3. Single-cell analysis indicates that over one-third of MLPs have the potential to efficiently generate cDCs. cDC1s generated from CMPs or MLPs do not exhibit differences in transcriptome or phenotype. These results demonstrate an early imprinting of the cDC lineage in human hematopoiesis and highlight the plasticity of developmental pathways giving rise to human DCs.

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases.

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Crawford, Melissa; Leclerc, Valerie; Dagnino, Lina

2017-08-15

Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSA mT/mG and Tyr::CreER T2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage. © 2017. Published by The Company of Biologists Ltd.

Structural studies of cyanobacterial PSII

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Da Fonseca, Paula Cristina Alves

2001-01-01

Photosystem II (PSII) is the photosynthetic transmembrane protein-pigment complex which utilises light energy to drive the splitting of water and release of oxygen, a unique reaction in biological systems. The determination of the structure of PSII at high resolution is required in order to understand its mechanisms of reaction. For this reason, methods have been developed to purify highly active PSII complexes from the thermophilic cyanobacterium Synechococcus elongate These complexes have been studied by high resolution electron microscopy, using both single particle analysis and electron crystallography. A 30A three-dimensional map of the cyanobacterial PSII complex was obtained by single particle analysis. The comparison of this map with structural data from the spinach PSII core dimer revealed that both complexes share similar overall size and shape. These data also allowed a discussion on the organisation and positioning of the extrinsic lumenal proteins within the cyanobacterial PSII complex. A Synechococcus elongatus PSII projection map, at a resolution of 20A, was determined by image processing of two-dimensional crystals formed by the in vitro reconstitution method. This was the first projection map obtained by electron crystallography of a cyanobacterial highly active PSII complex, with all the extrinsic subunits retained. The analysis of this map and its comparison with a 10A three-dimensional map recently obtained from the spinach PSII core dimer revealed a similar organisation of the main transmembrane subunits. Moreover, at the level of resolution of the present data it is possible to identify differences which can be related to the content and organisation of the small subunits forming the PSII complex from both organisms. Cytochrome b559, an important but incompletely understood PSII subunit, was purified and subjected to crystallisation trials in order to aid the interpretation of intermediate resolution PSII structural data. Small crystals were

Cyanobacterial evolution during the Precambrian

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Schirrmeister, Bettina E.; Sanchez-Baracaldo, Patricia; Wacey, David

2016-07-01

Life on Earth has existed for at least 3.5 billion years. Yet, relatively little is known of its evolution during the first two billion years, due to the scarceness and generally poor preservation of fossilized biological material. Cyanobacteria, formerly known as blue green algae were among the first crown Eubacteria to evolve and for more than 2.5 billion years they have strongly influenced Earth's biosphere. Being the only organism where oxygenic photosynthesis has originated, they have oxygenated Earth's atmosphere and hydrosphere, triggered the evolution of plants -being ancestral to chloroplasts- and enabled the evolution of complex life based on aerobic respiration. Having such a strong impact on early life, one might expect that the evolutionary success of this group may also have triggered further biosphere changes during early Earth history. However, very little is known about the early evolution of this phylum and ongoing debates about cyanobacterial fossils, biomarkers and molecular clock analyses highlight the difficulties in this field of research. Although phylogenomic analyses have provided promising glimpses into the early evolution of cyanobacteria, estimated divergence ages are often very uncertain, because of vague and insufficient tree-calibrations. Results of molecular clock analyses are intrinsically tied to these prior calibration points, hence improving calibrations will enable more precise divergence time estimations. Here we provide a review of previously described Precambrian microfossils, biomarkers and geochemical markers that inform upon the early evolution of cyanobacteria. Future research in micropalaeontology will require novel analyses and imaging techniques to improve taxonomic affiliation of many Precambrian microfossils. Consequently, a better understanding of early cyanobacterial evolution will not only allow for a more specific calibration of cyanobacterial and eubacterial phylogenies, but also provide new dates for the tree

After Nerve Injury, Lineage Tracing Shows That Myelin and Remak Schwann Cells Elongate Extensively and Branch to Form Repair Schwann Cells, Which Shorten Radically on Remyelination.

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Gomez-Sanchez, Jose A; Pilch, Kjara S; van der Lans, Milou; Fazal, Shaline V; Benito, Cristina; Wagstaff, Laura J; Mirsky, Rhona; Jessen, Kristjan R

2017-09-13

There is consensus that, distal to peripheral nerve injury, myelin and Remak cells reorganize to form cellular columns, Bungner's bands, which are indispensable for regeneration. However, knowledge of the structure of these regeneration tracks has not advanced for decades and the structure of the cells that form them, denervated or repair Schwann cells, remains obscure. Furthermore, the origin of these cells from myelin and Remak cells and their ability to give rise to myelin cells after regeneration has not been demonstrated directly, although these conversions are believed to be central to nerve repair. Using genetic lineage-tracing and scanning-block face electron microscopy, we show that injury of sciatic nerves from mice of either sex triggers extensive and unexpected Schwann cell elongation and branching to form long, parallel processes. Repair cells are 2- to 3-fold longer than myelin and Remak cells and 7- to 10-fold longer than immature Schwann cells. Remarkably, when repair cells transit back to myelinating cells, they shorten ∼7-fold to generate the typically short internodes of regenerated nerves. The present experiments define novel morphological transitions in injured nerves and show that repair Schwann cells have a cell-type-specific structure that differentiates them from other cells in the Schwann cell lineage. They also provide the first direct evidence using genetic lineage tracing for two basic assumptions in Schwann cell biology: that myelin and Remak cells generate the elongated cells that build Bungner bands in injured nerves and that such cells can transform to myelin cells after regeneration. SIGNIFICANCE STATEMENT After injury to peripheral nerves, the myelin and Remak Schwann cells distal to the injury site reorganize and modify their properties to form cells that support the survival of injured neurons, promote axon growth, remove myelin-associated growth inhibitors, and guide regenerating axons to their targets. We show that the

Two hemocyte lineages exist in silkworm larval hematopoietic organ.

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Yuichi Nakahara

Full Text Available BACKGROUND: Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. METHODOLOGY/PRINCIPAL FINDINGS: To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. CONCLUSIONS/SIGNIFICANCE: From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

Predicting cyanobacterial abundance, microcystin, and geosmin in a eutrophic drinking-water reservoir using a 14-year dataset

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Harris, Ted D.; Graham, Jennifer L.

2017-01-01

Cyanobacterial blooms degrade water quality in drinking water supply reservoirs by producing toxic and taste-and-odor causing secondary metabolites, which ultimately cause public health concerns and lead to increased treatment costs for water utilities. There have been numerous attempts to create models that predict cyanobacteria and their secondary metabolites, most using linear models; however, linear models are limited by assumptions about the data and have had limited success as predictive tools. Thus, lake and reservoir managers need improved modeling techniques that can accurately predict large bloom events that have the highest impact on recreational activities and drinking-water treatment processes. In this study, we compared 12 unique linear and nonlinear regression modeling techniques to predict cyanobacterial abundance and the cyanobacterial secondary metabolites microcystin and geosmin using 14 years of physiochemical water quality data collected from Cheney Reservoir, Kansas. Support vector machine (SVM), random forest (RF), boosted tree (BT), and Cubist modeling techniques were the most predictive of the compared modeling approaches. SVM, RF, and BT modeling techniques were able to successfully predict cyanobacterial abundance, microcystin, and geosmin concentrations <60,000 cells/mL, 2.5 µg/L, and 20 ng/L, respectively. Only Cubist modeling predicted maxima concentrations of cyanobacteria and geosmin; no modeling technique was able to predict maxima microcystin concentrations. Because maxima concentrations are a primary concern for lake and reservoir managers, Cubist modeling may help predict the largest and most noxious concentrations of cyanobacteria and their secondary metabolites.

Modulation of Hematopoietic Lineage Specification Impacts TREM2 Expression in Microglia-Like Cells Derived From Human Stem Cells.

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Amos, Peter J; Fung, Susan; Case, Amanda; Kifelew, Jerusalem; Osnis, Leah; Smith, Carole L; Green, Kevin; Naydenov, Alipi; Aloi, Macarena; Hubbard, Jesse J; Ramakrishnan, Aravind; Garden, Gwenn A; Jayadev, Suman

2017-01-01

Microglia are the primary innate immune cell type in the brain, and their dysfunction has been linked to a variety of central nervous system disorders. Human microglia are extraordinarily difficult to obtain for experimental investigation, limiting our ability to study the impact of human genetic variants on microglia functions. Previous studies have reported that microglia-like cells can be derived from human monocytes or pluripotent stem cells. Here, we describe a reproducible relatively simple method for generating microglia-like cells by first deriving embryoid body mesoderm followed by exposure to microglia relevant cytokines. Our approach is based on recent studies demonstrating that microglia originate from primitive yolk sac mesoderm distinct from peripheral macrophages that arise during definitive hematopoiesis. We hypothesized that functional microglia could be derived from human stem cells by employing BMP-4 mesodermal specification followed by exposure to microglia-relevant cytokines, M-CSF, GM-CSF, IL-34, and TGF-β. Using immunofluorescence microscopy, flow cytometry, and reverse transcription polymerase chain reaction, we observed cells with microglia morphology expressing a repertoire of markers associated with microglia: Iba1, CX3CR1, CD11b, TREM2, HexB, and P2RY12. These microglia-like cells maintain myeloid functional phenotypes including Aβ peptide phagocytosis and induction of pro-inflammatory gene expression in response to lipopolysaccharide stimulation. Addition of small molecules BIO and SB431542, previously demonstrated to drive definitive hematopoiesis, resulted in decreased surface expression of TREM2. Together, these data suggest that mesodermal lineage specification followed by cytokine exposure produces microglia-like cells in vitro from human pluripotent stem cells and that this phenotype can be modulated by factors influencing hematopoietic lineage in vitro.

Lineage plasticity-mediated therapy resistance in prostate cancer.

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Blee, Alexandra M; Huang, Haojie

2018-06-12

Therapy resistance is a significant challenge for prostate cancer treatment in clinic. Although targeted therapies such as androgen deprivation and androgen receptor (AR) inhibition are effective initially, tumor cells eventually evade these strategies through multiple mechanisms. Lineage reprogramming in response to hormone therapy represents a key mechanism that is increasingly observed. The studies in this area have revealed specific combinations of alterations present in adenocarcinomas that provide cells with the ability to transdifferentiate and perpetuate AR-independent tumor growth after androgen-based therapies. Interestingly, several master regulators have been identified that drive plasticity, some of which also play key roles during development and differentiation of the cell lineages in the normal prostate. Thus, further study of each AR-independent tumor type and understanding underlying mechanisms are warranted to develop combinational therapies that combat lineage plasticity in prostate cancer.

Cyanobacterial-algal cenoses in ordinary chernozems under the impact of different phytoameliorants

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Dubovik, I. E.; Suyundukov, Ya. T.; Khasanova, R. F.; Shalygina, R. R.

2016-04-01

General ecological and taxonomic characteristics of cyanobacterial-algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial-algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial-algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

Recruitment of Mediator Complex by Cell Type and Stage-Specific Factors Required for Tissue-Specific TAF Dependent Gene Activation in an Adult Stem Cell Lineage.

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Lu, Chenggang; Fuller, Margaret T

2015-12-01

Onset of terminal differentiation in adult stem cell lineages is commonly marked by robust activation of new transcriptional programs required to make the appropriate differentiated cell type(s). In the Drosophila male germ line stem cell lineage, the switch from proliferating spermatogonia to spermatocyte is accompanied by one of the most dramatic transcriptional changes in the fly, as over 1000 new transcripts turn on in preparation for meiosis and spermatid differentiation. Here we show that function of the coactivator complex Mediator is required for activation of hundreds of new transcripts in the spermatocyte program. Mediator appears to act in a sequential hierarchy, with the testis activating Complex (tMAC), a cell type specific form of the Mip/dREAM general repressor, required to recruit Mediator subunits to the chromatin, and Mediator function required to recruit the testis TAFs (tTAFs), spermatocyte specific homologs of subunits of TFIID. Mediator, tMAC and the tTAFs co-regulate expression of a major set of spermatid differentiation genes. The Mediator subunit Med22 binds the tMAC component Topi when the two are coexpressed in S2 cells, suggesting direct recruitment. Loss of Med22 function in spermatocytes causes meiosis I maturation arrest male infertility, similar to loss of function of the tMAC subunits or the tTAFs. Our results illuminate how cell type specific versions of the Mip/dREAM complex and the general transcription machinery cooperate to drive selective gene activation during differentiation in stem cell lineages.

Induction of multipotential hematopoietic progenitors from human pluripotent stem cells via re-specification of lineage-restricted precursors

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Doulatov, Sergei; Vo, Linda T.; Chou, Stephanie S.; Kim, Peter G.; Arora, Natasha; Li, Hu; Hadland, Brandon K.; Bernstein, Irwin D.; Collins, James J.; Zon, Leonard I.; Daley, George Q.

2013-01-01

Summary Human pluripotent stem cells (hPSCs) represent a promising source of patient-specific cells for disease modeling, drug screens, and cellular therapies. However, the inability to derive engraftable human hematopoietic stem and progenitor (HSPCs) has limited their characterization to in vitro assays. We report a strategy to re-specify lineage-restricted CD34+CD45+ myeloid precursors derived from hPSCs into multilineage progenitors that can be expanded in vitro and engraft in vivo. HOXA9, ERG, and RORA conferred self-renewal and multilineage potential in vitro and maintained primitive CD34+CD38− cells. Screening cells via transplantation revealed that two additional factors, SOX4 and MYB, were required for engraftment. Progenitors specified with all five factors gave rise to reproducible short-term engraftment with myeloid and erythroid lineages. Erythroid precursors underwent hemoglobin switching in vivo, silencing embryonic and activating adult globin expression. Our combinatorial screening approach establishes a strategy for obtaining transcription factor-mediated engraftment of blood progenitors from human pluripotent cells. PMID:24094326

Genome-wide comparative analysis of codon usage bias and codon context patterns among cyanobacterial genomes.

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Prabha, Ratna; Singh, Dhananjaya P; Sinha, Swati; Ahmad, Khurshid; Rai, Anil

2017-04-01

With the increasing accumulation of genomic sequence information of prokaryotes, the study of codon usage bias has gained renewed attention. The purpose of this study was to examine codon selection pattern within and across cyanobacterial species belonging to diverse taxonomic orders and habitats. We performed detailed comparative analysis of cyanobacterial genomes with respect to codon bias. Our analysis reflects that in cyanobacterial genomes, A- and/or T-ending codons were used predominantly in the genes whereas G- and/or C-ending codons were largely avoided. Variation in the codon context usage of cyanobacterial genes corresponded to the clustering of cyanobacteria as per their GC content. Analysis of codon adaptation index (CAI) and synonymous codon usage order (SCUO) revealed that majority of genes are associated with low codon bias. Codon selection pattern in cyanobacterial genomes reflected compositional constraints as major influencing factor. It is also identified that although, mutational constraint may play some role in affecting codon usage bias in cyanobacteria, compositional constraint in terms of genomic GC composition coupled with environmental factors affected codon selection pattern in cyanobacterial genomes. Copyright © 2016 Elsevier B.V. All rights reserved.

Bmi1 overexpression in the cerebellar granule cell lineage of mice affects cell proliferation and survival without initiating medulloblastoma formation

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Hourinaz Behesti

2013-01-01

BMI1 is a potent inducer of neural stem cell self-renewal and neural progenitor cell proliferation during development and in adult tissue homeostasis. It is overexpressed in numerous human cancers – including medulloblastomas, in which its functional role is unclear. We generated transgenic mouse lines with targeted overexpression of Bmi1 in the cerebellar granule cell lineage, a cell type that has been shown to act as a cell of origin for medulloblastomas. Overexpression of Bmi1 in granule cell progenitors (GCPs led to a decrease in cerebellar size due to decreased GCP proliferation and repression of the expression of cyclin genes, whereas Bmi1 overexpression in postmitotic granule cells improved cell survival in response to stress by altering the expression of genes in the mitochondrial cell death pathway and of Myc and Lef-1. Although no medulloblastomas developed in ageing cohorts of transgenic mice, crosses with Trp53−/− mice resulted in a low incidence of medulloblastoma formation. Furthermore, analysis of a large collection of primary human medulloblastomas revealed that tumours with a BMI1high TP53low molecular profile are significantly enriched in Group 4 human medulloblastomas. Our data suggest that different levels and timing of Bmi1 overexpression yield distinct cellular outcomes within the same cellular lineage. Importantly, Bmi1 overexpression at the GCP stage does not induce tumour formation, suggesting that BMI1 overexpression in GCP-derived human medulloblastomas probably occurs during later stages of oncogenesis and might serve to enhance tumour cell survival.

Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

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Babić Olivera B.

2013-01-01

Full Text Available Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 μmolpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 μmolpNP/s/dm3. The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 μmolpNP/s/dm3 compared to the activity of alkaline phosphatases (1.11-5.96 μmolpNP/s/dm3. Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions. [Projekat Ministarstva nauke Republike

iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions

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Wu, Jinhong; Yang, Jialong; Yang, Kai; Wang, Hongxia; Gorentla, Balachandra; Shin, Jinwook; Qiu, Yurong; Que, Loretta G.; Foster, W. Michael; Xia, Zhenwei; Chi, Hongbo; Zhong, Xiao-Ping

2014-01-01

Terminal maturation of invariant NKT (iNKT) cells from stage 2 (CD44+NK1.1–) to stage 3 (CD44+NK1.1+) is accompanied by a functional acquisition of a predominant IFN-γ–producing (iNKT-1) phenotype; however, some cells develop into IL-17–producing iNKT (iNKT-17) cells. iNKT-17 cells are rare and restricted to a CD44+NK1.1– lineage. It is unclear how iNKT terminal maturation is regulated and what factors mediate the predominance of iNKT-1 compared with iNKT-17. The tumor suppressor tuberous scl...

Late Archean mineralised cyanobacterial mats and their modern analogs

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Kazmierczak, J.; Altermann, W.; Kremer, B.; Kempe, S.; Eriksson, P. G.

2008-09-01

,c) reminiscent of common sheaths (glycocalix), typical for coccoidal colonial (pseudoparenchymatous) entophysalidacean or pleurocapsalean cyanobacteria (Fig. 2d-f). The remains of the coccoid sheaths and capsules are visible as a system of rimmed subglobular or irregularly polygonal pits separated from adjacent pits by 2-3 μm thick walls. Microprobe analyses show that the interiors of the pits are composed of almost pure calcium carbonate whereas the rims and walls of calcium carbonate with high admixture of silicates (mostly Al-Fe clay-like silicates) and dolomite. High magnification images of rims and walls confirm the microprobe data indicating authigenic character of the minerals forming both the carbonate infilling the pits interiors (CaCO3) and their rims and walls (CaCO3 + Al-Fe silicates + dolomite). EPSC Abstracts, Vol. 3, EPSC2008-A-00493, 2008 European Planetary Science Congress, Author(s) 2008 It seems that carbonates were the first mineral phase filling the spaces remained after the plasmolysis of the cyanobacterial cell contents, whereas the formation of silicates within the exopolysaccharides forming the bulk of the sheaths and capsules was a later diagenetic process. Microprobe analyses of mineralised modern coccoid cyanobacterial mats forming tower-like structures in the highly alkaline Lake Van, Turkey [3,4] display a set of elements indicative for the presence of authigenic carbonate and silicate minerals which are almost identical with that occurring in the studied Neoarchean samples. Also the optical and SEM images of polished and etched platelets of permineralised Lake Van microbialites are strikingly similar (Fig. 2d-f). Similarly as in modern cyanobacterial and other microbial mats, the process of early post mortem mineralisation, in the case of the Nauga Formation, was most probably associated with the action of heterotrophic bacteria upon the dead cyanobacterial biomass. Heterotrophic bacteria occupying EPS layers of living and dead cyanobacterial

Rearrangements of genes for the antigen receptor on T cells as markers of lineage and clonality in human lymphoid neoplasms.

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Waldmann, T A; Davis, M M; Bongiovanni, K F; Korsmeyer, S J

1985-09-26

The T alpha and T beta chains of the heterodimeric T-lymphocyte antigen receptor are encoded by separated DNA segments that recombine during T-cell development. We have used rearrangements of the T beta gene as a widely applicable marker of clonality in the T-cell lineage. We show that the T beta genes are used in both the T8 and T4 subpopulations of normal T cells and that Sézary leukemia, adult T-cell leukemia, and the non-B-lineage acute lymphoblastic leukemias are clonal expansions of T cells. Furthermore, circulating T cells from a patient with the T8-cell-predominantly lymphocytosis associated with granulocytopenia are shown to be monoclonal. Finally, the sensitivity and specificity of this tumor-associated marker have been exploited to monitor the therapy of a patient with adult T-cell leukemia. These unique DNA rearrangements provide insights into the cellular origin, clonality, and natural history of T-cell neoplasia.

Defined three-dimensional culture conditions mediate efficient induction of definitive endoderm lineage from human umbilical cord Wharton's jelly mesenchymal stem cells.

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Al Madhoun, Ashraf; Ali, Hamad; AlKandari, Sarah; Atizado, Valerie Lopez; Akhter, Nadeem; Al-Mulla, Fahd; Atari, Maher

2016-11-16

Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) are gaining increasing interest as an alternative source of stem cells for regenerative medicine applications. Definitive endoderm (DE) specification is a prerequisite for the development of vital organs such as liver and pancreas. Hence, efficient induction of the DE lineage from stem cells is crucial for subsequent generation of clinically relevant cell types. Here we present a defined 3D differentiation protocol of WJ-MSCs into DE cells. WJ-MSCs were cultured in suspension to generate spheroids, about 1500 cells each, for 7 days. The serum-free differentiation media contained specific growth factors, cytokines, and small molecules that specifically regulate signaling pathways including sonic hedgehog, bone morphogenetic protein, Activin/Wnt, and Notch. We obtained more than 85 % DE cells as shown with FACS analysis using antibodies directed against the DE marker CXCR4. In addition, biochemical and molecular analysis of bona-fide DE markers revealed a time-course induction of Sox17, CXCR4, and FoxA2. Focused PCR-based array also indicated a specific induction into the DE lineage. In this study, we report an efficient serum-free protocol to differentiate WJ-MSCs into DE cells utilizing 3D spheroid formation. Our approach might aid in the development of new protocols to obtain DE-derivative lineages including liver-like and pancreatic insulin-producing cells.

Engineered Murine HSCs Reconstitute Multi-lineage Hematopoiesis and Adaptive Immunity

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Yi-Fen Lu

2016-12-01

Full Text Available Hematopoietic stem cell (HSC transplantation is curative for malignant and genetic blood disorders, but is limited by donor availability and immune-mismatch. Deriving HSCs from patient-matched embryonic/induced-pluripotent stem cells (ESCs/iPSCs could address these limitations. Prior efforts in murine models exploited ectopic HoxB4 expression to drive self-renewal and enable multi-lineage reconstitution, yet fell short in delivering robust lymphoid engraftment. Here, by titrating exposure of HoxB4-ESC-HSC to Notch ligands, we report derivation of engineered HSCs that self-renew, repopulate multi-lineage hematopoiesis in primary and secondary engrafted mice, and endow adaptive immunity in immune-deficient recipients. Single-cell analysis shows that following engraftment in the bone marrow niche, these engineered HSCs further specify to a hybrid cell type, in which distinct gene regulatory networks of hematopoietic stem/progenitors and differentiated hematopoietic lineages are co-expressed. Our work demonstrates engineering of fully functional HSCs via modulation of genetic programs that govern self-renewal and lineage priming.

The fps/fes proto-oncogene regulates hematopoietic lineage output.

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Sangrar, Waheed; Gao, Yan; Zirngibl, Ralph A; Scott, Michelle L; Greer, Peter A

2003-12-01

The fps/fes proto-oncogene is abundantly expressed in myeloid cells, and the Fps/Fes cytoplasmic protein-tyrosine kinase is implicated in signaling downstream from hematopoietic cytokines, including interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and erythropoietin (EPO). Studies using leukemic cell lines have previously suggested that Fps/Fes contributes to granulomonocytic differentiation, and that it might play a more selective role in promoting survival and differentiation along the monocytic pathway. In this study we have used a genetic approach to explore the role of Fps/Fes in hematopoiesis. We used transgenic mice that tissue-specifically express a mutant human fps/fes transgene (fps(MF)) that was engineered to encode Fps/Fes kinase that is activated through N-terminal myristoylation (MFps). Hematopoietic function was assessed using lineage analysis, hematopoietic progenitor cell colony-forming assays, and biochemical approaches. fps(MF) transgenic mice displayed a skewed hematopoietic output reflected by increased numbers of circulating granulocytic and monocytic cells and a corresponding decrease in lymphoid cells. Bone marrow colony assays of progenitor cells revealed a significant increase in the number of both granulomonocytic and multi-lineage progenitors. A molecular analysis of signaling in mature monocytic cells showed that MFps promoted GM-CSF-induced STAT3, STAT5, and ERK1/2 activation. These observations support a role for Fps/Fes in signaling pathways that contribute to lineage determination at the level of multi-lineage hematopoietic progenitors as well as the more committed granulomonocytic progenitors.

Towards consistent generation of pancreatic lineage progenitors from human pluripotent stem cells.

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Rostovskaya, Maria; Bredenkamp, Nicholas; Smith, Austin

2015-10-19

Human pluripotent stem cells can in principle be used as a source of any differentiated cell type for disease modelling, drug screening, toxicology testing or cell replacement therapy. Type I diabetes is considered a major target for stem cell applications due to the shortage of primary human beta cells. Several protocols have been reported for generating pancreatic progenitors by in vitro differentiation of human pluripotent stem cells. Here we first assessed one of these protocols on a panel of pluripotent stem cell lines for capacity to engender glucose sensitive insulin-producing cells after engraftment in immunocompromised mice. We observed variable outcomes with only one cell line showing a low level of glucose response. We, therefore, undertook a systematic comparison of different methods for inducing definitive endoderm and subsequently pancreatic differentiation. Of several protocols tested, we identified a combined approach that robustly generated pancreatic progenitors in vitro from both embryo-derived and induced pluripotent stem cells. These findings suggest that, although there are intrinsic differences in lineage specification propensity between pluripotent stem cell lines, optimal differentiation procedures may consistently direct a substantial fraction of cells into pancreatic specification. © 2015 The Authors.

Recruitment of Mediator Complex by Cell Type and Stage-Specific Factors Required for Tissue-Specific TAF Dependent Gene Activation in an Adult Stem Cell Lineage.

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Chenggang Lu

2015-12-01

Full Text Available Onset of terminal differentiation in adult stem cell lineages is commonly marked by robust activation of new transcriptional programs required to make the appropriate differentiated cell type(s. In the Drosophila male germ line stem cell lineage, the switch from proliferating spermatogonia to spermatocyte is accompanied by one of the most dramatic transcriptional changes in the fly, as over 1000 new transcripts turn on in preparation for meiosis and spermatid differentiation. Here we show that function of the coactivator complex Mediator is required for activation of hundreds of new transcripts in the spermatocyte program. Mediator appears to act in a sequential hierarchy, with the testis activating Complex (tMAC, a cell type specific form of the Mip/dREAM general repressor, required to recruit Mediator subunits to the chromatin, and Mediator function required to recruit the testis TAFs (tTAFs, spermatocyte specific homologs of subunits of TFIID. Mediator, tMAC and the tTAFs co-regulate expression of a major set of spermatid differentiation genes. The Mediator subunit Med22 binds the tMAC component Topi when the two are coexpressed in S2 cells, suggesting direct recruitment. Loss of Med22 function in spermatocytes causes meiosis I maturation arrest male infertility, similar to loss of function of the tMAC subunits or the tTAFs. Our results illuminate how cell type specific versions of the Mip/dREAM complex and the general transcription machinery cooperate to drive selective gene activation during differentiation in stem cell lineages.

Impacts of microcystin, a cyanobacterial toxin, on laboratory rodents in vivo

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Andrea Ziková

2008-01-01

Full Text Available Cyanobacterial water blooms became a global problem/issue because beside a dramatic deterioration of water quality parameters they also produce cyanobacterial toxins being harmful for animals and humans. Cyanotoxins especially the most prominent one, microcystin-LR (MC-LR, are of major concern and they have been reported to cause even death of mammals following ingestion or ingurgitation due to hepatotoxic modes of action. The aim of the recent study is to summarize briefly the impacts of microcystin on laboratory rodents, mice and rats, being used as models for other mammals including human beings. Most experimental approaches used intraperitoneal rather than oral and intratracheal application of microcystins, especially MC-LR, being the most efficient way to induce adverse impacts on different target organs. However, no matter how the exposure of rodents was performed, microcystins induced severe harmful impacts on the different target organs, preferentially the liver, for instances hemorrhages and apoptosis in liver, liver tumours, adverse effects on gut, kidney, testis and epididymis including spermatogenesis, on lung, on serum parameters and on progeny. In addition to these histological findings, microcystin was found to affect specifically biochemical parameters of target organs such as enzymes e.g. GST, CAT, GR, GPX, SOD, AST, ALT, γ-GT, protein phosphatases, SDH, SoDH and LDH or stress proteins such as HSP-70 and further parameters such as hepatic sulfhydryl content, GSH depletion, total bilirubin, urea nitrogen, and creatinine. Gene array analyses revealed that microcystin affects genes related to actin organization, cell cycle, apoptosis, cellular redox potential, cell signalling, albumin metabolism, glucose homeostasis pathway and organic anion transport polypeptide system. In combination with a further proteomics approach the proteomic analyses indicate that liver apoptosis induced by microcystin can be induced by two pathways: the

A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage

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Faure, Emmanuel; Savy, Thierry; Rizzi, Barbara; Melani, Camilo; Stašová, Olga; Fabrèges, Dimitri; Špir, Róbert; Hammons, Mark; Čúnderlík, Róbert; Recher, Gaëlle; Lombardot, Benoît; Duloquin, Louise; Colin, Ingrid; Kollár, Jozef; Desnoulez, Sophie; Affaticati, Pierre; Maury, Benoît; Boyreau, Adeline; Nief, Jean-Yves; Calvat, Pascal; Vernier, Philippe; Frain, Monique; Lutfalla, Georges; Kergosien, Yannick; Suret, Pierre; Remešíková, Mariana; Doursat, René; Sarti, Alessandro; Mikula, Karol; Peyriéras, Nadine; Bourgine, Paul

2016-01-01

The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology. PMID:26912388

The 3’UTR of Nanos2 directs enrichment in the germ cell lineage of the sea urchin

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Oulhen, Nathalie; Yoshida, Takaya; Yajima, Mamiko; Song, Jia; Sakuma, Tetsushi; Sakamoto, Naoaki; Yamamoto, Takashi; Wessel, Gary M.

2013-01-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells during embryogenesis. Three nanos homologs are present in the genome of the sea urchin Strongylocentrotus purpuratus (Sp), and each nanos mRNA accumulates specifically in the small micromere (sMic) lineage. We found that a highly conserved element in the 3’ UTR of nanos2 is sufficient for reporter expression selectively in the sMic lineage: microinjection into a Sp fertilized egg of an RNA th...

Artificially accelerating the reversal of desertification: cyanobacterial inoculation facilitates the succession of vegetation communities.

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Lan, Shubin; Zhang, Qingyi; Wu, Li; Liu, Yongding; Zhang, Delu; Hu, Chunxiang

2014-01-01

Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.

Potential use of cyanobacterial species in bioremediation of ...

African Journals Online (AJOL)

Potential use of cyanobacterial species in bioremediation of industrial effluents. ... African Journal of Biotechnology ... Abstract. This study investigated the potential degradation of industrial effluents by environmental species of cyanobacteria.

Lineage-specific enhancers activate self-renewal genes in macrophages and embryonic stem cells.

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Soucie, Erinn L; Weng, Ziming; Geirsdóttir, Laufey; Molawi, Kaaweh; Maurizio, Julien; Fenouil, Romain; Mossadegh-Keller, Noushine; Gimenez, Gregory; VanHille, Laurent; Beniazza, Meryam; Favret, Jeremy; Berruyer, Carole; Perrin, Pierre; Hacohen, Nir; Andrau, J-C; Ferrier, Pierre; Dubreuil, Patrice; Sidow, Arend; Sieweke, Michael H

2016-02-12

Differentiated macrophages can self-renew in tissues and expand long term in culture, but the gene regulatory mechanisms that accomplish self-renewal in the differentiated state have remained unknown. Here we show that in mice, the transcription factors MafB and c-Maf repress a macrophage-specific enhancer repertoire associated with a gene network that controls self-renewal. Single-cell analysis revealed that, in vivo, proliferating resident macrophages can access this network by transient down-regulation of Maf transcription factors. The network also controls embryonic stem cell self-renewal but is associated with distinct embryonic stem cell-specific enhancers. This indicates that distinct lineage-specific enhancer platforms regulate a shared network of genes that control self-renewal potential in both stem and mature cells. Copyright © 2016, American Association for the Advancement of Science.

Immunoliposome-mediated delivery of neomycin phosphotransferase for the lineage-specific selection of differentiated/committed stem cell progenies: potential advantages over transfection with marker genes, fluorescence-activated and magnetic affinity cell-sorting.

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Heng, Boon Chin; Cao, Tong

2005-01-01

A major challenge in the therapeutic application of stem cells in regenerative medicine is the lineage-specific selection of their committed/differentiated progenies for transplantation. This is necessary to avoid engraftment of undesired lineages at the transplantation site, i.e. fibroblastic scar tissue, as well as to enhance the efficacy of transplantation therapy. Commonly used techniques for lineage-specific selection of committed/differentiated stem cell progenies include marker gene transfection, fluorescence-activated (FACS) and magnetic-affinity (MACS) cell-sorting. Nevertheless, these have their disadvantages for therapeutic applications. Marker gene transfection invariably leads to permanent genetic modification of stem cells, which in turn limits their use in human clinical therapy due to overwhelming ethical and safety concerns. FACS requires expensive instrumentation and highly-skilled personnel, and is unsuited for handling bulk quantities of cells that would almost certainly be required for transplantation therapy. MACS is a cheaper alternative, but the level of purity attained is also reduced. A possible novel approach that has yet to be investigated is immunoliposome-mediated delivery of neomycin phosphotranferase (NPT) for lineage-specific selection of stem cell progenies. This would avoid permanent genetic modification to the cell, unlike recombinant NPT expression linked to activation of specific promoter sequences. Moreover, it could potentially provide a much more practical and cost-effective alternative for handling bulk quantities of cells that would be required for transplantation therapy, as compared to FACS or MACS. As such, this alternative approach needs to be rigorously investigated, in view of its potentially useful applications in stem cell therapeutics.

Cadmium uptake capacity of an indigenous cyanobacterial strain, Nostoc entophytum ISC32: new insight into metal uptake in microgravity-simulating conditions.

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Alidoust, Leila; Soltani, Neda; Modiri, Sima; Haghighi, Omid; Azarivand, Aisan; Khajeh, Khosro; Shahbani Zahiri, Hossein; Vali, Hojatollah; Akbari Noghabi, Kambiz

2016-02-01

Among nine cyanobacterial strains isolated from oil-contaminated regions in southern Iran, an isolate with maximum cadmium uptake capacity was selected and identified on the basis of analysis of morphological criteria and 16S rRNA gene sequence similarity as Nostoc entophytum (with 99% similarity). The isolate was tentatively designated N. entophytum ISC32. The phylogenetic affiliation of the isolates was determined on the basis of their 16S rRNA gene sequence. The maximum amount of Cd(II) adsorbed by strain ISC32 was 302.91 mg g(-1) from an initial exposure to a solution with a Cd(II) concentration of 150 mg l(-1). The cadmium uptake by metabolically active cells of cyanobacterial strain N. entophytum ISC32, retained in a clinostat for 6 days to simulate microgravity conditions, was examined and compared with that of ground control samples. N. entophytum ISC32 under the influence of microgravity was able to take up cadmium at amounts up to 29% higher than those of controls. The activity of antioxidant enzymes including catalase and peroxidase was increased in strain ISC32 exposed to microgravity conditions in a clinostat for 6 days, as catalase activity of the cells was more than three times higher than that of controls. The activity of the peroxidase enzyme increased by 36% compared with that of the controls. Membrane lipid peroxidation was also increased in the cells retained under microgravity conditions, up to 2.89-fold higher than in non-treated cells. Images obtained using scanning electron microscopy showed that cyanobacterial cells form continuous filaments which are drawn at certain levels, while the cells placed in a clinostat appeared as round-shaped, accumulated together and distorted to some extent.

RNA-seq based identification and mutant validation of gene targets related to ethanol resistance in cyanobacterial Synechocystis sp. PCC 6803

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Wang Jiangxin

2012-12-01

Full Text Available Abstract Background Fermentation production of biofuel ethanol consumes agricultural crops, which will compete directly with the food supply. As an alternative, photosynthetic cyanobacteria have been proposed as microbial factories to produce ethanol directly from solar energy and CO2. However, the ethanol productivity from photoautotrophic cyanobacteria is still very low, mostly due to the low tolerance of cyanobacterial systems to ethanol stress. Results To build a foundation necessary to engineer robust ethanol-producing cyanobacterial hosts, in this study we applied a quantitative transcriptomics approach with a next-generation sequencing technology, combined with quantitative reverse-transcript PCR (RT-PCR analysis, to reveal the global metabolic responses to ethanol in model cyanobacterial Synechocystis sp. PCC 6803. The results showed that ethanol exposure induced genes involved in common stress responses, transporting and cell envelope modification. In addition, the cells can also utilize enhanced polyhydroxyalkanoates (PHA accumulation and glyoxalase detoxication pathway as means against ethanol stress. The up-regulation of photosynthesis by ethanol was also further confirmed at transcriptional level. Finally, we used gene knockout strains to validate the potential target genes related to ethanol tolerance. Conclusion RNA-Seq based global transcriptomic analysis provided a comprehensive view of cellular response to ethanol exposure. The analysis provided a list of gene targets for engineering ethanol tolerance in cyanobacterium Synechocystis.

Inhibition of gap-junctional intercellular communication and activation of mitogen-activated protein kinases by cyanobacterial extracts--indications of novel tumor-promoting cyanotoxins?

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Bláha, Ludĕk; Babica, Pavel; Hilscherová, Klára; Upham, Brad L

2010-01-01

Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.

SIRPA, VCAM1 and CD34 identify discrete lineages during early human cardiovascular development

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Rhys J.P. Skelton

2014-07-01

Full Text Available The study of human cardiogenesis would benefit from a detailed cell lineage fate map akin to that established for the haematopoietic lineages. Here we sought to define cell lineage relationships based on the expression of NKX2-5 and the cell surface markers VCAM1, SIRPA and CD34 during human cardiovascular development. Expression of NKX2-5GFP was used to identify cardiac progenitors and cardiomyocytes generated during the differentiation of NKX2-5GFP/w human embryonic stem cells (hESCs. Cardiovascular cell lineages sub-fractionated on the basis of SIRPA, VCAM1 and CD34 expression were assayed for differentiation potential and gene expression. The NKX2-5posCD34pos population gave rise to endothelial cells that rapidly lost NKX2-5 expression in culture. Conversely, NKX2-5 expression was maintained in myocardial committed cells, which progressed from being NKX2-5posSIRPApos to NKX2-5posSIRPAposVCAM1pos. Up-regulation of VCAM1 was accompanied by the expression of myofilament markers and reduced clonal capacity, implying a restriction of cell fate potential. Combinatorial expression of NKX2-5, SIRPA, VCAM1 and CD34 can be used to define discrete stages of cardiovascular cell lineage differentiation. These markers identify specific stages of cardiomyocyte and endothelial lineage commitment and, thus provide a scaffold for establishing a fate map of early human cardiogenesis.

Combined exposure of carps (Cyprinus carpio L.) to cyanobacterial biomass and white spot disease.

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Palikova, Miroslava; Navratil, Stanislav; Papezikova, Ivana; Ambroz, Petr; Vesely, Tomas; Pokorova, Dagmar; Mares, Jan; Adamovsky, Ondrej; Navratil, Lukas; Kopp, Radovan

2012-01-01

Under environmental conditions, fish can be exposed to multiple stressors including natural toxins and infectious agents at the same time. This study brings new knowledge on the effects of controlled exposure to multiple stressors in fish. The aim of this study was to test the hypothesis that influence of cyanobacterial biomass and an infection agent represented by the white spot disease can combine to enhance the effects on fish. Common carps were divided into four groups, each with 40 specimens for 20 days: control group, cyanobacterial biomass exposed group, Ichthyophthirius multifiliis-infected fish (Ich) and cyanobacterial biomass-exposed fish + Ichthyophthirius multifiliis-infected fish. During the experiment we evaluated the clinical signs, mortality, selected haematological parameters, immune parameters and toxin accumulation. There was no mortality in control fish and cyanobacterial biomass-exposed fish. One specimen died in Ichthyophthirius multifiliis-infected fish and the combined exposure resulted in the death of 13 specimens. The whole leukocyte counts (WBC) of the control group did not show any significant differences. Cyanobacteria alone caused a significant increase of the WBC on day 13 (p≤0.05) and on day 20 (p≤0.01). Also, I. multifiliis caused a significant elevation of WBC (p≤0.01) on day 20. Co-exposition resulted in WBC increased on day 13 and decrease on day 20, but the changes were not significant. It is evident from the differential leukocyte counts that while the increase of WBC in the group exposed to cyanobacteria was caused by elevation of lymphocytes, the increase in the group infected by I. multifiliis was due to the increase of myeloid cells. It well corresponds with the integral of chemiluminescence in the group infected by I. multifiliis, which is significantly elevated on day 20 in comparison with all other groups. We can confirm additive action of different agents on the immune system of fish. While single agents seemed to

What happens in the thymus does not stay in the thymus: how T cells recycle the CD4+-CD8+ lineage commitment transcriptional circuitry to control their function

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Vacchio, Melanie S.; Bosselut, Rémy

2016-01-01

MHC-restricted CD4+ and CD8+ T cell are at the core of most adaptive immune responses. Although these cells carry distinct functions, they arise from a common precursor during thymic differentiation, in a developmental sequence that matches CD4 and CD8 expression and functional potential with MHC restriction. While the transcriptional control of CD4+-CD8+ lineage choice in the thymus is now better understood, less was known about what maintains the CD4+- and CD8+-lineage integrity of mature T cells. In this review, we discuss the mechanisms that establish in the thymus, and maintain in post-thymic cells, the separation of these lineages. We focus on recent studies that address the mechanisms of epigenetic control of Cd4 expression and emphasize how maintaining a transcriptional circuitry nucleated around Thpok and Runx proteins, the key architects of CD4+-CD8+ lineage commitment in the thymus, is critical for CD4+ T cell helper functions. PMID:27260768

T-lineage blast crisis of chronic myelogenous leukemia: simple record of 4 cases

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Kartika W. Taroeno-Hariadi

2005-09-01

Full Text Available Blast crisis (BC transformation in chronic myelogenous leukemia (CML can involve each differentiation lineage of the hematopoietic system, i.e. granulocyte, monocyte, erythrocyte, megakaryocyte, and lymphocyte lineage. The lymphoid blast crisis (BC leukemia cells usually belong to B-lineage, commonly having the phenotype of Pre-B stage of the B-lineage, in which cell-surface immunoglobulin (sIg is not yet expressed. In contrast, T-lineage BC of CML is extremely rare. The objective of this study is to describe the fenotype, fusion transcript of bcr-abl, TdT, and cytoplasmic CD3 in T-lineage BC CML cases. Case report study. This report shows a simple summary of 4 cases of T-lineage BC of CML which have been collected in the phenotypic and genotypic analysis study for 17 years (1987-2004. In all cases, the chromosomal analysis revealed the presence of t(9;22(q34;q11 at presentation. Cell surface analysis were done at diagnosis. Cases’ mononuclear cells stored as 10% DMSO were retrieved to be performed reverse transcription (RT PCR BCR-ABL multiplex to demonstrate the presence of the fusion transcript of bcr-abl. RT-PCR was also performed for detecting the expression of cytoplasmic CD3ε and terminal deoxynucleotydil transferase (TdT. The results of cell surface antigen (CSA at presentation showed that 1 case was CD7+, CD5-, and CD2-; 1 case CD7+, CD5+, and CD2-; and 2 cases CD7+, CD5+ and CD2+ indicating that all these T-lineage BC of CML cells show the phenotype of pre-(pro- thymic stage phenotype. In the present study, two cases showed b2a2, one e1a2, and one negative bcr-abl transcript. The RT-PCR revealed the presence of CD3ε mRNA in all cases, and TdT mRNA in only one case. These results can constitute a basis for the future analysis of T-lineage BC of CML from now on. (Med J Indones 2005; 14: 184-9Keywords: chronic myelogenous leukemia (CML, blastic crisis (BC, T-lineage, bcr-abl fusion gene, CDε, TdT

Lineage relationship of prostate cancer cell types based on gene expression

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Ware Carol B

2011-05-01

Full Text Available Abstract Background Prostate tumor heterogeneity is a major factor in disease management. Heterogeneity could be due to multiple cancer cell types with distinct gene expression. Of clinical importance is the so-called cancer stem cell type. Cell type-specific transcriptomes are used to examine lineage relationship among cancer cell types and their expression similarity to normal cell types including stem/progenitor cells. Methods Transcriptomes were determined by Affymetrix DNA array analysis for the following cell types. Putative prostate progenitor cell populations were characterized and isolated by expression of the membrane transporter ABCG2. Stem cells were represented by embryonic stem and embryonal carcinoma cells. The cancer cell types were Gleason pattern 3 (glandular histomorphology and pattern 4 (aglandular sorted from primary tumors, cultured prostate cancer cell lines originally established from metastatic lesions, xenografts LuCaP 35 (adenocarcinoma phenotype and LuCaP 49 (neuroendocrine/small cell carcinoma grown in mice. No detectable gene expression differences were detected among serial passages of the LuCaP xenografts. Results Based on transcriptomes, the different cancer cell types could be clustered into a luminal-like grouping and a non-luminal-like (also not basal-like grouping. The non-luminal-like types showed expression more similar to that of stem/progenitor cells than the luminal-like types. However, none showed expression of stem cell genes known to maintain stemness. Conclusions Non-luminal-like types are all representatives of aggressive disease, and this could be attributed to the similarity in overall gene expression to stem and progenitor cell types.

Human mesenchymal stem cells derived from limb bud can differentiate into all three embryonic germ layers lineages.

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Jiao, Fei; Wang, Juan; Dong, Zhao-Lun; Wu, Min-Juan; Zhao, Ting-Bao; Li, Dan-Dan; Wang, Xin

2012-08-01

Mesenchymal stem cells (MSCs) have been isolated from many sources, including adults and fetuses. Previous studies have demonstrated that, compared with their adult counterpart, fetal MSCs with several remarkable advantages may be a better resource for clinical applications. In this study, we successfully isolated a rapidly proliferating cell population from limb bud of aborted fetus and termed them "human limb bud-derived mesenchymal stem cells" (hLB-MSCs). Characteristics of their morphology, phenotype, cell cycle, and differentiation properties were analyzed. These adherent cell populations have a typically spindle-shaped morphology. Flow cytometry analysis showed that hLB-MSCs are positive for CD13, CD29, CD90, CD105, and CD106, but negative for CD3, CD4, CD5, CD11b, CD14, CD15, CD34, CD45, CD45RA, and HLA-DR. The detection of cell cycle from different passages indicated that hLB-MSCs have a similar potential for propagation during long culture in vitro. The most novel finding here is that, in addition to their mesodermal differentiation (osteoblasts and adipocytes), hLB-MSCs can also differentiated into extramesenchymal lineages, such as neural (ectoderm) and hepatic (endoderm) progenies. These results indicate that hLB-MSCs have a high level of plasticity and can differentiate into cell lineages from all three embryonic layers in vitro.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins.

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Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma; Cillero-Castro, Carmen; Budzyńska, Agnieszka; Goldyn, Ryszard; Kozak, Anna; Rosińska, Joanna; Szeląg-Wasielewska, Elżbieta; Domek, Piotr; Jakubowska-Krepska, Natalia; Kwasizur, Kinga; Messyasz, Beata; Pełechaty, Aleksandra; Pełechaty, Mariusz; Kokocinski, Mikolaj; García-Murcia, Ana; Real, Monserrat; Romans, Elvira; Noguero-Ribes, Jordi; Duque, David Parreño; Fernández-Morán, Elísabeth; Karakaya, Nusret; Häggqvist, Kerstin; Demir, Nilsun; Beklioğlu, Meryem; Filiz, Nur; Levi, Eti E.; Iskin, Uğur; Bezirci, Gizem; Tavşanoğlu, Ülkü Nihan; Özhan, Koray; Gkelis, Spyros; Panou, Manthos; Fakioglu, Özden; Avagianos, Christos; Kaloudis, Triantafyllos; Çelik, Kemal; Yilmaz, Mete; Marcé, Rafael; Catalán, Nuria; Bravo, Andrea G.; Buck, Moritz; Colom-Montero, William; Mustonen, Kristiina; Pierson, Don; Yang, Yang; Raposeiro, Pedro M.; Gonçalves, Vítor; Antoniou, Maria G.; Tsiarta, Nikoletta; McCarthy, Valerie; Perello, Victor C.; Feldmann, Tõnu; Laas, Alo; Panksep, Kristel; Tuvikene, Lea; Gagala, Ilona; Mankiewicz-Boczek, Joana; Yağcı, Meral Apaydın; Çınar, Şakir; Çapkın, Kadir; Yağcı, Abdulkadir; Cesur, Mehmet; Bilgin, Fuat; Bulut, Cafer; Uysal, Rahmi; Obertegger, Ulrike; Boscaini, Adriano; Flaim, Giovanna; Salmaso, Nico; Cerasino, Leonardo; Richardson, Jessica; Visser, Petra M.; Verspagen, Jolanda M. H.; Karan, Tünay; Soylu, Elif Neyran; Maraşlıoğlu, Faruk; Napiórkowska-Krzebietke, Agnieszka; Ochocka, Agnieszka; Pasztaleniec, Agnieszka; Antão-Geraldes, Ana M.; Vasconcelos, Vitor; Morais, João; Vale, Micaela; Köker, Latife; Akçaalan, Reyhan; Albay, Meriç; Špoljarić Maronić, Dubravka; Stević, Filip; Žuna Pfeiffer, Tanja; Fonvielle, Jeremy; Straile, Dietmar; Rothhaupt, Karl-Otto; Hansson, Lars-Anders; Urrutia-Cordero, Pablo; Bláha, Luděk; Geriš, Rodan; Fránková, Markéta; Koçer, Mehmet Ali Turan; Alp, Mehmet Tahir; Remec-Rekar, Spela; Elersek, Tina; Triantis, Theodoros; Zervou, Sevasti-Kiriaki; Hiskia, Anastasia; Haande, Sigrid; Skjelbred, Birger; Madrecka, Beata; Nemova, Hana; Drastichova, Iveta; Chomova, Lucia; Edwards, Christine; Sevindik, Tuğba Ongun; Tunca, Hatice; Önem, Burçin; Aleksovski, Boris; Krstić, Svetislav; Vucelić, Itana Bokan; Nawrocka, Lidia; Salmi, Pauliina; Machado-Vieira, Danielle; de Oliveira, Alinne Gurjão; Delgado-Martín, Jordi; García, David; Cereijo, Jose Luís; Gomà, Joan; Trapote, Mari Carmen; Vegas-Vilarrúbia, Teresa; Obrador, Biel; Grabowska, Magdalena; Karpowicz, Maciej; Chmura, Damian; Úbeda, Bárbara; Gálvez, José Ángel; Özen, Arda; Christoffersen, Kirsten Seestern; Warming, Trine Perlt; Kobos, Justyna; Mazur-Marzec, Hanna; Pérez-Martínez, Carmen; Ramos-Rodríguez, Eloísa; Arvola, Lauri; Alcaraz-Párraga, Pablo; Toporowska, Magdalena; Pawlik-Skowronska, Barbara; Niedźwiecki, Michał; Pęczuła, Wojciech; Leira, Manel; Hernández, Armand; Moreno-Ostos, Enrique; Blanco, José María; Rodríguez, Valeriano; Montes-Pérez, Jorge Juan; Palomino, Roberto L.; Rodríguez-Pérez, Estela; Carballeira, Rafael; Camacho, Antonio; Picazo, Antonio; Rochera, Carlos; Santamans, Anna C.; Ferriol, Carmen; Romo, Susana; Soria, Juan Miguel; Dunalska, Julita; Sieńska, Justyna; Szymański, Daniel; Kruk, Marek; Kostrzewska-Szlakowska, Iwona; Jasser, Iwona; Žutinić, Petar; Gligora Udovič, Marija; Plenković-Moraj, Anđelka; Frąk, Magdalena; Bańkowska-Sobczak, Agnieszka; Wasilewicz, Michał; Özkan, Korhan; Maliaka, Valentini; Kangro, Kersti; Grossart, Hans-Peter; Paerl, Hans W.; Carey, Cayelan C.; Ibelings, Bas W.

2018-04-13

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

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Evanthia Mantzouki

2018-04-01

Full Text Available Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins. Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a and cytotoxins (e.g., cylindrospermopsin due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Stochastic differentiation into an osteoclast lineage from cloned macrophage-like cells

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Shin-Ichi, E-mail: shayashi@med.tottori-u.ac.jp [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan); Murata, Akihiko; Okuyama, Kazuki; Shimoda, Yuhki; Hikosaka, Mari [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan); Yasuda, Hisataka [Planning and Development, Bioindustry Division, Oriental Yeast Co., Ltd, Itabashi-Ku, Tokyo 174-8505 (Japan); Yoshino, Miya [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan)

2012-11-16

Highlights: Black-Right-Pointing-Pointer The frequency of C7 differentiation into osteoclast was low and constant. Black-Right-Pointing-Pointer Only extended C7 cell cultures exponentially increased osteoclast+ cultures. Black-Right-Pointing-Pointer C7 cell differentiation into committed osteoclast precursors is on 'autopilot'. Black-Right-Pointing-Pointer The system may maintain the stem cell self-renewal and differentiation. -- Abstract: Differentiation into osteoclasts is induced by a macrophage colony-stimulating factor and receptor activator of nuclear-factor {kappa}B ligand. The macrophage-like cell line, C7 has the potential to differentiate into osteoclasts when it is cultured with both factors for 6 days. Although C7 is an established cell line, the frequency of differentiation into this lineage was less than 10%, and the ratio was maintained at a constant level, even after repeated cloning. In this study, to increase the differentiation of C7 cells to osteoclasts, C7 derivative treatments with several activators and/or inhibitors were performed for 3 days prior to setting osteoclast induction analysis; however, a reagent to significantly up-regulate the frequency of differentiation was not found. Only extended cultures for osteoclastogenesis exponentially increased the frequency of osteoclast precursors. It is likely that C7 cell differentiation into committed osteoclast precursors is on 'autopilot' rather than requiring specific signals to drive this process.

Stochastic differentiation into an osteoclast lineage from cloned macrophage-like cells

International Nuclear Information System (INIS)

Hayashi, Shin-Ichi; Murata, Akihiko; Okuyama, Kazuki; Shimoda, Yuhki; Hikosaka, Mari; Yasuda, Hisataka; Yoshino, Miya

2012-01-01

Highlights: ► The frequency of C7 differentiation into osteoclast was low and constant. ► Only extended C7 cell cultures exponentially increased osteoclast+ cultures. ► C7 cell differentiation into committed osteoclast precursors is on ‘autopilot’. ► The system may maintain the stem cell self-renewal and differentiation. -- Abstract: Differentiation into osteoclasts is induced by a macrophage colony-stimulating factor and receptor activator of nuclear-factor κB ligand. The macrophage-like cell line, C7 has the potential to differentiate into osteoclasts when it is cultured with both factors for 6 days. Although C7 is an established cell line, the frequency of differentiation into this lineage was less than 10%, and the ratio was maintained at a constant level, even after repeated cloning. In this study, to increase the differentiation of C7 cells to osteoclasts, C7 derivative treatments with several activators and/or inhibitors were performed for 3 days prior to setting osteoclast induction analysis; however, a reagent to significantly up-regulate the frequency of differentiation was not found. Only extended cultures for osteoclastogenesis exponentially increased the frequency of osteoclast precursors. It is likely that C7 cell differentiation into committed osteoclast precursors is on ‘autopilot’ rather than requiring specific signals to drive this process.

Accumulation of cyanobacterial toxins in freshwater "seafood" and its consequences for public health: A review

NARCIS (Netherlands)

Ibelings, B.W.; Chorus, I.

2007-01-01

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in “seafood” collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and

The Geographic Distribution of Liver Cancer in Canada Does Not Associate with Cyanobacterial Toxin Exposure

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Meaghan A. Labine

2015-11-01

Full Text Available Background: The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer. Objective: To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada. Methods: A negative binomial regression model was employed based on previously identified risk factors for liver cancer. Results: No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences. Discussion and Conclusions: The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada.

Bioconductor workflow for single-cell RNA sequencing: Normalization, dimensionality reduction, clustering, and lineage inference [version 1; referees: 1 approved, 2 approved with reservations

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Fanny Perraudeau

2017-07-01

Full Text Available Novel single-cell transcriptome sequencing assays allow researchers to measure gene expression levels at the resolution of single cells and offer the unprecendented opportunity to investigate at the molecular level fundamental biological questions, such as stem cell differentiation or the discovery and characterization of rare cell types. However, such assays raise challenging statistical and computational questions and require the development of novel methodology and software. Using stem cell differentiation in the mouse olfactory epithelium as a case study, this integrated workflow provides a step-by-step tutorial to the methodology and associated software for the following four main tasks: (1 dimensionality reduction accounting for zero inflation and over dispersion and adjusting for gene and cell-level covariates; (2 cell clustering using resampling-based sequential ensemble clustering; (3 inference of cell lineages and pseudotimes; and (4 differential expression analysis along lineages.

A novel earth observation based ecological indicator for cyanobacterial blooms

Science.gov (United States)

Anttila, Saku; Fleming-Lehtinen, Vivi; Attila, Jenni; Junttila, Sofia; Alasalmi, Hanna; Hällfors, Heidi; Kervinen, Mikko; Koponen, Sampsa

2018-02-01

Cyanobacteria form spectacular mass occurrences almost annually in the Baltic Sea. These harmful algal blooms are the most visible consequences of marine eutrophication, driven by a surplus of nutrients from anthropogenic sources and internal processes of the ecosystem. We present a novel Cyanobacterial Bloom Indicator (CyaBI) targeted for the ecosystem assessment of eutrophication in marine areas. The method measures the current cyanobacterial bloom situation (an average condition of recent 5 years) and compares this to the estimated target level for 'good environmental status' (GES). The current status is derived with an index combining indicative bloom event variables. As such we used seasonal information from the duration, volume and severity of algal blooms derived from earth observation (EO) data. The target level for GES was set by using a remote sensing based data set named Fraction with Cyanobacterial Accumulations (FCA; Kahru & Elmgren, 2014) covering years 1979-2014. Here a shift-detection algorithm for time series was applied to detect time-periods in the FCA data where the level of blooms remained low several consecutive years. The average conditions from these time periods were transformed into respective CyaBI target values to represent target level for GES. The indicator is shown to pass the three critical factors set for marine indicator development, namely it measures the current status accurately, the target setting can be scientifically proven and it can be connected to the ecosystem management goal. An advantage of the CyaBI method is that it's not restricted to the data used in the development work, but can be complemented, or fully applied, by using different types of data sources providing information on cyanobacterial accumulations.

Close Link Between Harmful Cyanobacterial Dominance and Associated Bacterioplankton in a Tropical Eutrophic Reservoir

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Iame A. Guedes

2018-03-01

Full Text Available Cyanobacteria tend to become the dominant phytoplankton component in eutrophic freshwater environments during warmer seasons. However, general observations of cyanobacterial adaptive advantages in these circumstances are insufficient to explain the prevalence of one species over another in a bloom period, which may be related to particular strategies and interactions with other components of the plankton community. In this study, we present an integrative view of a mixed cyanobacterial bloom occurring during a warm, rainy period in a tropical hydropower reservoir. We used high-throughput sequencing to follow temporal shifts in the dominance of cyanobacterial genera and shifts in the associated heterotrophic bacteria community. The bloom occurred during late spring-summer and included two distinct periods. The first period corresponded to Microcystis aeruginosa complex (MAC dominance with a contribution from Dolichospermum circinale; this pattern coincided with high water retention time and low transparency. The second period corresponded to Cylindrospermopsis raciborskii and Synechococcus spp. dominance, and the reservoir presented lower water retention time and higher water transparency. The major bacterial phyla were primarily Cyanobacteria and Proteobacteria, followed by Actinobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes. Temporal shifts in the dominance of cyanobacterial genera were not only associated with physical features of the water but also with shifts in the associated heterotrophic bacteria. The MAC bloom was associated with a high abundance of Bacteroidetes, particularly Cytophagales. In the second bloom period, Planctomycetes increased in relative abundance, five Planctomycetes OTUs were positively correlated with Synechococcus or C. raciborskii OTUs. Our results suggest specific interactions of the main cyanobacterial genera with certain groups of the heterotrophic bacterial community. Thus, considering biotic

An integrated method for removal of harmful cyanobacterial blooms in eutrophic lakes

International Nuclear Information System (INIS)

Wang Zhicong; Li Dunhai; Qin Hongjie; Li Yinxia

2012-01-01

As the eutrophication of lakes becomes an increasingly widespread phenomenon, cyanobacterial blooms are occurring in many countries. Although some research has been reported, there is currently no good method for bloom removal. We propose here a new two-step integrated approach to resolve this problem. The first step is the inactivation of the cyanobacteria via the addition of H 2 O 2 . We found 60 mg/L was the lowest effective dose for a cyanobacterial concentration corresponding to 100 μg/L chlorophyll-a. The second step is the flocculation and sedimentation of the inactivated cyanobacteria. We found the addition of lake sediment clay (2 g/L) plus polymeric ferric sulfate (20 mg/L) effectively deposited them on the lake bottom. Since algaecides and flocculants had been used separately in previous reports, we innovatively combined these two types of reagents to remove blooms from the lake surface and to improve the dissolved oxygen content of lake sediments. - Graphical abstract: The mechanism for the removal of cyanobacterial blooms by using H 2 O 2 , polymeric ferric sulfate (PFS) and lake sediment clay. Display Omitted Highlights: ► We combined algaecide and flocculants together to control cyanobacterial blooms. ► H 2 O 2 was used to irreversibly inactivate the photosynthesis of cyanobacteria. ► Lake sediment clay and polymeric ferric sulfate were used to deposit cyanobacteria. ► Removal rate was very high and re-suspension rate was very low under disturbance. ► The inactivated cyanobacteria could not serve as a seed source for the next bloom. - Inactivation by H 2 O 2 and sedimentation using polymeric ferric sulfate and sediment clay demonstrated high integrated efficiency in removal of cyanobacterial blooms.

CRX is a diagnostic marker of retinal and pineal lineage tumors.

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Sandro Santagata

2009-11-01

Full Text Available CRX is a homeobox transcription factor whose expression and function is critical to maintain retinal and pineal lineage cells and their progenitors. To determine the biologic and diagnostic potential of CRX in human tumors of the retina and pineal, we examined its expression in multiple settings.Using situ hybridization and immunohistochemistry we show that Crx RNA and protein expression are exquisitely lineage restricted to retinal and pineal cells during normal mouse and human development. Gene expression profiling analysis of a wide range of human cancers and cancer cell lines also supports that CRX RNA is highly lineage restricted in cancer. Immunohistochemical analysis of 22 retinoblastomas and 13 pineal parenchymal tumors demonstrated strong expression of CRX in over 95% of these tumors. Importantly, CRX was not detected in the majority of tumors considered in the differential diagnosis of pineal region tumors (n = 78. The notable exception was medulloblastoma, 40% of which exhibited CRX expression in a heterogeneous pattern readily distinguished from that seen in retino-pineal tumors.These findings describe new potential roles for CRX in human cancers and highlight the general utility of lineage restricted transcription factors in cancer biology. They also identify CRX as a sensitive and specific clinical marker and a potential lineage dependent therapeutic target in retinoblastoma and pineoblastoma.

All-trans retinoic acid promotes neural lineage entry by pluripotent embryonic stem cells via multiple pathways

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Fang Bo

2009-07-01

Full Text Available Abstract Background All-trans retinoic acid (RA is one of the most important morphogens with pleiotropic actions. Its embryonic distribution correlates with neural differentiation in the developing central nervous system. To explore the precise effects of RA on neural differentiation of mouse embryonic stem cells (ESCs, we detected expression of RA nuclear receptors and RA-metabolizing enzymes in mouse ESCs and investigated the roles of RA in adherent monolayer culture. Results Upon addition of RA, cell differentiation was directed rapidly and exclusively into the neural lineage. Conversely, pharmacological interference with RA signaling suppressed this neural differentiation. Inhibition of fibroblast growth factor (FGF signaling did not suppress significantly neural differentiation in RA-treated cultures. Pharmacological interference with extracellular signal-regulated kinase (ERK pathway or activation of Wnt pathway effectively blocked the RA-promoted neural specification. ERK phosphorylation was enhanced in RA-treated cultures at the early stage of differentiation. Conclusion RA can promote neural lineage entry by ESCs in adherent monolayer culture systems. This effect depends on RA signaling and its crosstalk with the ERK and Wnt pathways.

Cyanobacterial diversity and a new acaryochloris-like symbiont from Bahamian sea-squirts.

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Susanna López-Legentil

Full Text Available Symbiotic interactions between ascidians (sea-squirts and microbes are poorly understood. Here we characterized the cyanobacteria in the tissues of 8 distinct didemnid taxa from shallow-water marine habitats in the Bahamas Islands by sequencing a fragment of the cyanobacterial 16S rRNA gene and the entire 16S-23S rRNA internal transcribed spacer region (ITS and by examining symbiont morphology with transmission electron (TEM and confocal microscopy (CM. As described previously for other species, Trididemnum spp. mostly contained symbionts associated with the Prochloron-Synechocystis group. However, sequence analysis of the symbionts in Lissoclinum revealed two unique clades. The first contained a novel cyanobacterial clade, while the second clade was closely associated with Acaryochloris marina. CM revealed the presence of chlorophyll d (chl d and phycobiliproteins (PBPs within these symbiont cells, as is characteristic of Acaryochloris species. The presence of symbionts was also observed by TEM inside the tunic of both the adult and larvae of L. fragile, indicating vertical transmission to progeny. Based on molecular phylogenetic and microscopic analyses, Candidatus Acaryochloris bahamiensis nov. sp. is proposed for this symbiotic cyanobacterium. Our results support the hypothesis that photosymbiont communities in ascidians are structured by host phylogeny, but in some cases, also by sampling location.

Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

Energy Technology Data Exchange (ETDEWEB)

Stuart, Rhona K.; Mayali, Xavier; Boaro, Amy A.; Zemla, Adam; Everroad, R. Craig; Nilson, Daniel; Weber, Peter K.; Lipton, Mary; Bebout, Brad M.; Pett-Ridge, Jennifer; Thelen, Michael P.

2016-06-28

>IMPORTANCECyanobacteria are globally distributed primary producers, and the fate of their fixed C influences microbial biogeochemical cycling. This fate is complicated by cyanobacterial degradation and assimilation of organic matter, but because cyanobacteria are assumed to be poor competitors for organic matter consumption, regulation of this process is not well tested. In mats and biofilms, this is especially relevant because cyanobacteria produce an extensive organic extracellular matrix, providing the community with a rich source of nutrients. Light is a well-known regulator of cyanobacterial metabolism, so we characterized the effects of light availability on the incorporation of organic matter. Using stable isotope tracing at the single-cell level, we quantified photoautotroph assimilation under different metabolic conditions and integrated the results with proteomics to elucidate metabolic status. We found that cyanobacteria effectively compete for organic matter in the light and the dark and that nutrient requirements and community interactions contribute to cycling of extracellular organic matter.

PHF6 regulates phenotypic plasticity through chromatin organization within lineage-specific genes.

Science.gov (United States)

Soto-Feliciano, Yadira M; Bartlebaugh, Jordan M E; Liu, Yunpeng; Sánchez-Rivera, Francisco J; Bhutkar, Arjun; Weintraub, Abraham S; Buenrostro, Jason D; Cheng, Christine S; Regev, Aviv; Jacks, Tyler E; Young, Richard A; Hemann, Michael T

2017-05-15

Developmental and lineage plasticity have been observed in numerous malignancies and have been correlated with tumor progression and drug resistance. However, little is known about the molecular mechanisms that enable such plasticity to occur. Here, we describe the function of the plant homeodomain finger protein 6 (PHF6) in leukemia and define its role in regulating chromatin accessibility to lineage-specific transcription factors. We show that loss of Phf6 in B-cell leukemia results in systematic changes in gene expression via alteration of the chromatin landscape at the transcriptional start sites of B-cell- and T-cell-specific factors. Additionally, Phf6 KO cells show significant down-regulation of genes involved in the development and function of normal B cells, show up-regulation of genes involved in T-cell signaling, and give rise to mixed-lineage lymphoma in vivo. Engagement of divergent transcriptional programs results in phenotypic plasticity that leads to altered disease presentation in vivo, tolerance of aberrant oncogenic signaling, and differential sensitivity to frontline and targeted therapies. These findings suggest that active maintenance of a precise chromatin landscape is essential for sustaining proper leukemia cell identity and that loss of a single factor (PHF6) can cause focal changes in chromatin accessibility and nucleosome positioning that render cells susceptible to lineage transition. © 2017 Soto-Feliciano et al.; Published by Cold Spring Harbor Laboratory Press.

Characterization of cyanobacterial communities from high-elevation lakes in the Bolivian Andes

Science.gov (United States)

Fleming, Erich D.; Prufert-Bebout, Leslie

2010-06-01

The Bolivian Altiplano is a harsh environment for life with high solar irradiation (visible and UVR), below freezing temperatures, and some of the lowest precipitation rates on the planet. However, microbial life is visibly abundant in small isolated refugia of spring or snowmelt-fed lakes. In this study, we characterized the cyanobacterial composition of a variety of microbial mats present in three lake systems: Laguna Blanca, Laguna Verde (elevation 4300 m), and a summit lake in the Licancabur Volcano cone (elevation 5970 m). These lakes and their adjacent geothermal springs present an interesting diversity of environments within a geographically small region (5 km2). From these sites, 78 cyanobacterial cultures were isolated in addition to ˜400 cyanobacterial 16S rRNA gene sequences from environmental genomic DNA. Based on microscopy, cultivation, and molecular analyses, these communities contained many heterocytous, nitrogen-fixing cyanobacteria (e.g., Calothrix, Nostoc, Nodularia) as well as a large number of cyanobacteria belonging to the form-genus Leptolyngbya. More than a third (37%) of all taxa in this study were new species (≤96% 16S rRNA gene sequence identity), and 11% represented new and novel taxa distantly related (≤93% identity) to any known cyanobacteria. This is one of the few studies to characterize cyanobacterial communities based on both cultivation-dependent and cultivation-independent analyses.

A census of nuclear cyanobacterial recruits in the plant kingdom.

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Szabolcs Makai

Full Text Available The plastids and mitochondria of the eukaryotic cell are of endosymbiotic origin. These events occurred ~2 billion years ago and produced significant changes in the genomes of the host and the endosymbiont. Previous studies demonstrated that the invasion of land affected plastids and mitochondria differently and that the paths of mitochondrial integration differed between animals and plants. Other studies examined the reasons why a set of proteins remained encoded in the organelles and were not transferred to the nuclear genome. However, our understanding of the functional relations of the transferred genes is insufficient. In this paper, we report a high-throughput phylogenetic analysis to identify genes of cyanobacterial origin for plants of different levels of complexity: Arabidopsis thaliana, Chlamydomonas reinhardtii, Physcomitrella patens, Populus trichocarpa, Selaginella moellendorffii, Sorghum bicolor, Oryza sativa, and Ostreococcus tauri. Thus, a census of cyanobacterial gene recruits and a study of their function are presented to better understand the functional aspects of plastid symbiogenesis. From algae to angiosperms, the GO terms demonstrated a gradual expansion over functionally related genes in the nuclear genome, beginning with genes related to thylakoids and photosynthesis, followed by genes involved in metabolism, and finally with regulation-related genes, primarily in angiosperms. The results demonstrate that DNA is supplied to the nuclear genome on a permanent basis with no regard to function, and only what is needed is kept, which thereby expands on the GO space along the related genes.

Assessment of the mutagenic potential of cyanobacterial extracts and pure cyanotoxins.

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Sieroslawska, Anna

2013-11-01

The aim of the study was to assess the mutagenic potential of extracts obtained from the cyanobacterial bloom-forming cells harvested from the water body located in Lubelszczyzna region of southeastern Poland. Three cyanotoxins, microcystin-LR, cylindrospermopsin and anatoxin-a were detected in some of the studied samples in different concentrations. All extracts were assessed for their potential mutagenic effects with the use of a short-term bacterial assay, the Ames test. Mutagenic activity was observed in four of all ten studied extracts, mainly toward the Salmonella typhimurium TA100 strain. On the contrary, the cyanotoxins in purified forms occurred not to be mutagenic or cytotoxic towards S. typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2 uvrA and WP2 [pKM101] up to a concentration of 10 μg/ml. Similarly, there were no effects after bacteria exposure to the mixture of purified toxins. It has been also detected that after fractionation, genotoxic impact of previously mutagenic extracts was weaker and the highest potency in revertant induction possessed fractions containing very hydrophilic compounds. The results indicate, that while tested cyanotoxins were not directly responsible for the observed mutagenicity of the extracts analysed, some synergistic interactions with other unidentified cyanobacterial-derived factors involved in the process are possible. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pancreas lineage allocation and specification are regulated by sphingosine-1-phosphate signalling

Science.gov (United States)

Serafimidis, Ioannis; Rodriguez-Aznar, Eva; Lesche, Mathias; Yoshioka, Kazuaki; Takuwa, Yoh; Dahl, Andreas; Pan, Duojia; Gavalas, Anthony

2017-01-01

During development, progenitor expansion, lineage allocation, and implementation of differentiation programs need to be tightly coordinated so that different cell types are generated in the correct numbers for appropriate tissue size and function. Pancreatic dysfunction results in some of the most debilitating and fatal diseases, including pancreatic cancer and diabetes. Several transcription factors regulating pancreas lineage specification have been identified, and Notch signalling has been implicated in lineage allocation, but it remains unclear how these processes are coordinated. Using a combination of genetic approaches, organotypic cultures of embryonic pancreata, and genomics, we found that sphingosine-1-phosphate (S1p), signalling through the G protein coupled receptor (GPCR) S1pr2, plays a key role in pancreas development linking lineage allocation and specification. S1pr2 signalling promotes progenitor survival as well as acinar and endocrine specification. S1pr2-mediated stabilisation of the yes-associated protein (YAP) is essential for endocrine specification, thus linking a regulator of progenitor growth with specification. YAP stabilisation and endocrine cell specification rely on Gαi subunits, revealing an unexpected specificity of selected GPCR intracellular signalling components. Finally, we found that S1pr2 signalling posttranscriptionally attenuates Notch signalling levels, thus regulating lineage allocation. Both S1pr2-mediated YAP stabilisation and Notch attenuation are necessary for the specification of the endocrine lineage. These findings identify S1p signalling as a novel key pathway coordinating cell survival, lineage allocation, and specification and linking these processes by regulating YAP levels and Notch signalling. Understanding lineage allocation and specification in the pancreas will shed light in the origins of pancreatic diseases and may suggest novel therapeutic approaches. PMID:28248965

Cyanobacterial composition and spatial distribution based on pyrosequencing data in the Gurbantunggut Desert, Northwestern China.

Science.gov (United States)

Zhang, Bingchang; Li, Renhui; Xiao, Peng; Su, Yangui; Zhang, Yuanming

2016-03-01

Cyanobacteria are the primary colonizers and form a dominant component of soil photosynthetic communities in biological soil crusts. They are crucial in improving soil environments, namely accumulating soil carbon and nitrogen. Many classical studies have examined cyanobacterial diversity in desert crusts, but relatively few comprehensive molecular surveys have been conducted. We used 454 pyrosequencing of 16S rRNA to investigate cyanobacterial composition and distribution on regional scales in the Gurbantunggut Desert. The relationship between cyanobacterial distribution and environmental factors was also explored. A total of 24,973 cyanobacteria partial 16S rRNA gene sequences were obtained, and 507OTUs were selected, as most OTUs had very few reads. Among these, 347 OTU sequences were of cyanobacteria origin, belonging to Oscillatoriales, Nostocales, Chroococcales, and uncultured cyanobacterium clone, respectively. Microcoleus vaginatus, Chroococcidiopsis spp. and M. steenstrupii were the dominant species in most areas of the Gurbantunggut Desert. Compared with other desert, the Gurbantunggut Desert differed in the prominence of Chroococcidiopsis spp. and lack of Pseudanabaenales. Species composition and abundance of cyanobacteria also showed distinct variations. Soil texture, precipitation, and nutrients and salt levels affected cyanobacterial distribution. Increased precipitation was helpful in improving cyanobacterial diversity. A higher content of coarse sand promoted the colonization and growth of Oscillatoriales and some phylotypes of Chroococcales. The fine-textured soil with higher nutrients and salts supported more varied populations of cyanobacteria, namely some heterocystous cyanobacteria. The results suggested that the Gurbantunggut Desert was rich in cyanobacteria and that precipitation was a primary regulating factor for cyanobacterial composition on a regional scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vitro cultured progenitors and precursors of cardiac cell lineages from human normal and post-ischemic hearts

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F Di Meglio

2009-08-01

Full Text Available The demonstration of the presence of dividing primitive cells in damaged hearts has sparked increased interest about myocardium regenerative processes. We examined the rate and the differentiation of in vitro cultured resident cardiac primitive cells obtained from pathological and normal human hearts in order to evaluate the activation of progenitors and precursors of cardiac cell lineages in post-ischemic human hearts. The precursors and progenitors of cardiomyocyte, smooth muscle and endothelial lineage were identified by immunocytochemistry and the expression of characteristic markers was studied by western blot and RT-PCR. The amount of proteins characteristic for cardiac cells (a-SA and MHC, VEGFR-2 and FVIII, SMA for the precursors of cardiomyocytes, endothelial and smooth muscle cells, respectively inclines toward an increase in both a-SA and MHC. The increased levels of FVIII and VEGFR2 are statistically significant, suggesting an important re-activation of neoangiogenesis. At the same time, the augmented expression of mRNA for Nkx 2.5, the trascriptional factor for cardiomyocyte differentiation, confirms the persistence of differentiative processes in terminally injured hearts. Our study would appear to confirm the activation of human heart regeneration potential in pathological conditions and the ability of its primitive cells to maintain their proliferative capability in vitro. The cardiac cell isolation method we used could be useful in the future for studying modifications to the microenvironment that positively influence cardiac primitive cell differentiation or inhibit, or retard, the pathological remodeling and functional degradation of the heart.

The anhydrobiotic cyanobacterial cell

International Nuclear Information System (INIS)

Potts, M.

1996-01-01

The cyanobacterium Nostoc commune has been developed as the prokaryotic model for the anhydrobiotic cell and it provides the means to answer fundamental questions about desiccation tolerance. The anhydrobiotic cell is characterized by its singular lack of water — with contents as low as 0.02 g H 2 O g -1 dry weight. These levels are orders of magnitude lower than those found either in bacterial spores or in cells subjected to acute salt (osmotic) stress. Mechanisms that contribute to the desiccation tolerance of N. commune include the selective stabilization of anhydrous proteins, the secretion of water- and lipid-soluble UV-absorbing pigments, and the secretion of a complex glycan that immobilizes the cells, immobilizes water stress proteins and the UV-absorbing pigments, and which may confer the properties of a mechanical glass upon colonies. Rehydration of desiccated cells induces an instantaneous resumption of metabolic activities, including membrane transport and global lipid biosynthesis. These initial recoveries may not follow classical Arrhenius-based kinetics. The rehydrating cell exhibits a stringent, stepwise recovery of physiological capacities beginning with respiration, then photosynthesis and finally nitrogen fixation. Protein turnover, de novo protein synthesis and a rapid rise in the intracellular ATP pool accompany these recoveries. During the early stages of rehydration, the de novo transcription of one gene set (rpoC1C2) is achieved using an extant DNA-dependent RNA polymerase holoenzyme that remains stable in desiccated cells. These properties of desiccation-tolerant cyanobacleria, present in extant forms such as N. commune and Chroococcidiopsis spp., may have been utilized by the eoanhydrobiotes. However, it is the desiccation-tolerant cyanobacterium as a whole, and not some collection of disparate properties, that must be considered as the primary strategy for the achievement of desiccation tolerance. (author)

Comparison of Cytotoxic Activity in Leukemic Lineages Reveals Important Features of β-Hairpin Antimicrobial Peptides.

Science.gov (United States)

Buri, Marcus V; Torquato, Heron F Vieira; Barros, Carlos Castilho; Ide, Jaime S; Miranda, Antonio; Paredes-Gamero, Edgar J

2017-07-01

Several reports described different modes of cell death triggered by antimicrobial peptides (AMPs) due to direct effects on membrane disruption, and more recently by apoptosis and necrosis-like patterns. Cytotoxic curves of four β-hairpin AMPs (gomesin, protegrin, tachyplesin, and polyphemusin) were obtained from several human leukemic lineages and normal monocytes and Two cell lines were then selected based on their cytotoxic sensitivity. One was sensitive to AMPs (K562) and the other resistant (KG-1) and their effect compared between these lineages. Thus, these lineages were chosen to further investigate biological features related with their cytotoxicities to AMPs. Stimulation with AMPs produced cell death, with activation of caspase-3, in K562 lineage. Increase on the fluidity of plasmatic membrane by reducing cholesterol potentiated cytotoxicity of AMPs in both lineages. Quantification of internal and external gomesin binding to the cellular membrane of both K562 and KG-1 cells showed that more peptide is accumulated inside of K562 cells. Additionally, evaluation of multi-drug resistant pumps activity showed that KG-1 has more activity than K562 lineage. A comparison of intrinsic gene patterns showed great differences between K562 and KG-1, but stimulation with gomesin promoted few changes in gene expression patterns. Differences in internalization process through the plasma membrane, multidrug resistance pumps activity, and gene expression pattern are important features to AMPs regulated cell death. J. Cell. Biochem. 118: 1764-1773, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement

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Shelley Rogers

2015-03-01

Full Text Available Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures and with biomass enrichment (by centrifugation or GF/C filtration. After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

Transcriptional and posttranscriptional regulation of cyanobacterial photosynthesis.

Science.gov (United States)

Wilde, Annegret; Hihara, Yukako

2016-03-01

Cyanobacteria are well established model organisms for the study of oxygenic photosynthesis, nitrogen metabolism, toxin biosynthesis, and salt acclimation. However, in comparison to other model bacteria little is known about regulatory networks, which allow cyanobacteria to acclimate to changing environmental conditions. The current work has begun to illuminate how transcription factors modulate expression of different photosynthetic regulons. During the past few years, the research on other regulatory principles like RNA-based regulation showed the importance of non-protein regulators for bacterial lifestyle. Investigations on modulation of photosynthetic components should elucidate the contributions of all factors within the context of a larger regulatory network. Here, we focus on regulation of photosynthetic processes including transcriptional and posttranscriptional mechanisms, citing examples from a limited number of cyanobacterial species. Though, the general idea holds true for most species, important differences exist between various organisms, illustrating diversity of acclimation strategies in the very heterogeneous cyanobacterial clade. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux. Copyright © 2015 Elsevier B.V. All rights reserved.

A curated database of cyanobacterial strains relevant for modern taxonomy and phylogenetic studies

OpenAIRE

Ramos, Vitor; Morais, Jo?o; Vasconcelos, Vitor M.

2017-01-01

The dataset herein described lays the groundwork for an online database of relevant cyanobacterial strains, named CyanoType (http://lege.ciimar.up.pt/cyanotype). It is a database that includes categorized cyanobacterial strains useful for taxonomic, phylogenetic or genomic purposes, with associated information obtained by means of a literature-based curation. The dataset lists 371 strains and represents the first version of the database (CyanoType v.1). Information for each strain includes st...

TLM-Tracker: software for cell segmentation, tracking and lineage analysis in time-lapse microscopy movies.

Science.gov (United States)

Klein, Johannes; Leupold, Stefan; Biegler, Ilona; Biedendieck, Rebekka; Münch, Richard; Jahn, Dieter

2012-09-01

Time-lapse imaging in combination with fluorescence microscopy techniques enable the investigation of gene regulatory circuits and uncovered phenomena like culture heterogeneity. In this context, computational image processing for the analysis of single cell behaviour plays an increasing role in systems biology and mathematical modelling approaches. Consequently, we developed a software package with graphical user interface for the analysis of single bacterial cell behaviour. A new software called TLM-Tracker allows for the flexible and user-friendly interpretation for the segmentation, tracking and lineage analysis of microbial cells in time-lapse movies. The software package, including manual, tutorial video and examples, is available as Matlab code or executable binaries at http://www.tlmtracker.tu-bs.de.

Dynamics of cyanobacterial bloom formation during short-term hydrodynamic fluctuation in a large shallow, eutrophic, and wind-exposed Lake Taihu, China.

Science.gov (United States)

Wu, Tingfeng; Qin, Boqiang; Zhu, Guangwei; Luo, Liancong; Ding, Yanqing; Bian, Geya

2013-12-01

Short-term hydrodynamic fluctuations caused by extreme weather events are expected to increase worldwide because of global climate change, and such fluctuations can strongly influence cyanobacterial blooms. In this study, the cyanobacterial bloom disappearance and reappearance in Lake Taihu, China, in response to short-term hydrodynamic fluctuations, was investigated by field sampling, long-term ecological records, high-frequency sensors and MODIS satellite images. The horizontal drift caused by the dominant easterly wind during the phytoplankton growth season was mainly responsible for cyanobacterial biomass accumulation in the western and northern regions of the lake and subsequent bloom formation over relatively long time scales. The cyanobacterial bloom changed slowly under calm or gentle wind conditions. In contrast, the short-term bloom events within a day were mainly caused by entrainment and disentrainment of cyanobacterial colonies by wind-induced hydrodynamics. Observation of a westerly event in Lake Taihu revealed that when the 30 min mean wind speed (flow speed) exceeded the threshold value of 6 m/s (5.7 cm/s), cyanobacteria in colonies were entrained by the wind-induced hydrodynamics. Subsequently, the vertical migration of cyanobacterial colonies was controlled by hydrodynamics, resulting in thorough mixing of algal biomass throughout the water depth and the eventual disappearance of surface blooms. Moreover, the intense mixing can also increase the chance for forming larger and more cyanobacterial colonies, namely, aggregation. Subsequently, when the hydrodynamics became weak, the cyanobacterial colonies continuously float upward without effective buoyancy regulation, and cause cyanobacterial bloom explosive expansion after the westerly. Furthermore, the results of this study indicate that the strong wind happening frequently during April and October can be an important cause of the formation and expansion of cyanobacterial blooms in Lake Taihu.

Quantifying Selective Pressures Driving Bacterial Evolution Using Lineage Analysis

Science.gov (United States)

Lambert, Guillaume; Kussell, Edo

2015-01-01

Organisms use a variety of strategies to adapt to their environments and maximize long-term growth potential, but quantitative characterization of the benefits conferred by the use of such strategies, as well as their impact on the whole population's rate of growth, remains challenging. Here, we use a path-integral framework that describes how selection acts on lineages—i.e., the life histories of individuals and their ancestors—to demonstrate that lineage-based measurements can be used to quantify the selective pressures acting on a population. We apply this analysis to Escherichia coli bacteria exposed to cyclical treatments of carbenicillin, an antibiotic that interferes with cell-wall synthesis and affects cells in an age-dependent manner. While the extensive characterization of the life history of thousands of cells is necessary to accurately extract the age-dependent selective pressures caused by carbenicillin, the same measurement can be recapitulated using lineage-based statistics of a single surviving cell. Population-wide evolutionary pressures can be extracted from the properties of the surviving lineages within a population, providing an alternative and efficient procedure to quantify the evolutionary forces acting on a population. Importantly, this approach is not limited to age-dependent selection, and the framework can be generalized to detect signatures of other trait-specific selection using lineage-based measurements. Our results establish a powerful way to study the evolutionary dynamics of life under selection and may be broadly useful in elucidating selective pressures driving the emergence of antibiotic resistance and the evolution of survival strategies in biological systems.

Lineage fate of ductular reactions in liver injury and carcinogenesis.

Science.gov (United States)

Jörs, Simone; Jeliazkova, Petia; Ringelhan, Marc; Thalhammer, Julian; Dürl, Stephanie; Ferrer, Jorge; Sander, Maike; Heikenwalder, Mathias; Schmid, Roland M; Siveke, Jens T; Geisler, Fabian

2015-06-01

Ductular reactions (DRs) are observed in virtually all forms of human liver disease; however, the histogenesis and function of DRs in liver injury are not entirely understood. It is widely believed that DRs contain bipotential liver progenitor cells (LPCs) that serve as an emergency cell pool to regenerate both cholangiocytes and hepatocytes and may eventually give rise to hepatocellular carcinoma (HCC). Here, we used a murine model that allows highly efficient and specific lineage labeling of the biliary compartment to analyze the histogenesis of DRs and their potential contribution to liver regeneration and carcinogenesis. In multiple experimental and genetic liver injury models, biliary cells were the predominant precursors of DRs but lacked substantial capacity to produce new hepatocytes, even when liver injuries were prolonged up to 12 months. Genetic modulation of NOTCH and/or WNT/β-catenin signaling within lineage-tagged DRs impaired DR expansion but failed to redirect DRs from biliary differentiation toward the hepatocyte lineage. Further, lineage-labeled DRs did not produce tumors in genetic and chemical HCC mouse models. In summary, we found no evidence in our system to support mouse biliary-derived DRs as an LPC pool to replenish hepatocytes in a quantitatively relevant way in injury or evidence that DRs give rise to HCCs.

Ancestral trees for modeling stem cell lineages genetically rather than functionally: understanding mutation accumulation and distinguishing the restrictive cancer stem cell propagation theory and the unrestricted cell propagation theory of human tumorigenesis.

Science.gov (United States)

Shibata, Darryl K; Kern, Scott E

2008-01-01

Cancer stem cells either could be rare or common in tumors, constituting the major distinction between the two fundamentally opposed theoretical models of tumor progression: A newer and restrictive stem cell propagation model, in which the stem cells are a small and special minority of the tumor cells, and a standard older model, an unrestricted cell proliferation theory, in which many or most tumor cells are capable of indefinite generations of cell division. Stem cells of tumors are difficult to quantitate using functional assays, and the validity of the most common assays is seriously questioned. Nonetheless, stem cells are an essential component of any tumorigenesis model. Alternative approaches to studying tumor stem cells should be explored. Cell populations can be conceived of as having a genealogy, a relationship of cells to their ancestral lineage, from the zygote to the adult cells or neoplasms. Models using ancestral trees thus offer an anatomic and genetic means to "observe" stem cells independent of artificial conditions. Ancestral trees broaden our attention backward along a lineage, to the zygote stage, and thereby add insight into how the mutations of tumors accumulate. It is possible that a large fraction of mutations in a tumor originate from normal, endogenous, replication errors (nearly all being passenger mutations) occurring prior to the emergence of the first transformed cell. Trees can be constructed from experimental measurements - molecular clocks - of real human tissues and tumors. Detailed analysis of single-cell methylation patterns, heritable yet slightly plastic, now can provide this information in the necessary depth. Trees based on observations of molecular clocks may help us to distinguish between competing theories regarding the proliferative properties among cells of actual human tumors, to observe subtle and difficult phenomena such as the extinction of stem lineages, and to address the origins and rates of mutations in various

Fatty Acid Composition of Six Freshwater Wild Cyanobacterial Species

Czech Academy of Sciences Publication Activity Database

Řezanka, Tomáš; Dor, I.; Prell, Aleš; Dembitský, V. M.

2003-01-01

Roč. 48, č. 1 (2003), s. 71-75 ISSN 0015-5632 Institutional research plan: CEZ:AV0Z5020903 Keywords : cyanobacterial spcies * freshwater wild Subject RIV: EE - Microbiology, Virology Impact factor: 0.857, year: 2003

Reduced reactivation from dormancy but maintained lineage choice of human mesenchymal stem cells with donor age.

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Verena Dexheimer

Full Text Available UNLABELLED: Mesenchymal stem cells (MSC are promising for cell-based regeneration therapies but up to date it is still controversial whether their function is maintained throughout ageing. Aim of this study was to address whether frequency, activation in vitro, replicative function, and in vitro lineage choice of MSC is maintained throughout ageing to answer the question whether MSC-based regeneration strategies should be restricted to younger individuals. MSC from bone marrow aspirates of 28 donors (5-80 years were characterized regarding colony-forming unit-fibroblast (CFU-F numbers, single cell cloning efficiency (SSCE, osteogenic, adipogenic and chondrogenic differentiation capacity in vitro. Alkaline phosphatase (ALP activity, mineralization, Oil Red O content, proteoglycan- and collagen type II deposition were quantified. While CFU-F frequency was maintained, SSCE and early proliferation rate decreased significantly with advanced donor age. MSC with higher proliferation rate before start of induction showed stronger osteogenic, adipogenic and chondrogenic differentiation. MSC with high osteogenic capacity underwent better chondrogenesis and showed a trend to better adipogenesis. Lineage choice was, however, unaltered with age. CONCLUSION: Ageing influenced activation from dormancy and replicative function of MSC in a way that it may be more demanding to mobilize MSC to fast cell growth at advanced age. Since fast proliferation came along with high multilineage capacity, the proliferation status of expanded MSC rather than donor age may provide an argument to restrict MSC-based therapies to certain individuals.

Mitigating cyanobacterial blooms: how effective are 'effective microorganisms'?

NARCIS (Netherlands)

Lürling, M.F.L.L.W.; Tolman, Y.; Euwe, M.

2009-01-01

This study examined the effects of 'Effective Microorganisms (EM)' on the growth of cyanobacteria, and their ability to terminate cyanobacterial blooms. The EM was tested in the form of 'mudballs' or 'Bokashi-balls', and as a suspension (EM-A) in laboratory experiments. No growth inhibition was

Cyanobacterial Community Structure In Lithifying Mats of A Yellowstone Hotspring-Implications for Precambrian Stromatolite Biocomplexity

Science.gov (United States)

Lau, Evan; Nash, C. Z.; Vogler, D. R.; Cullings, K.; DeVincenzi, Donald (Technical Monitor)

2002-01-01

Denaturing Gradient Gel Electrophoresis (DGGE) of partial 16S rRNA gene sequences was used to investigate the molecular biodiversity of cyanobacterial communities inhabiting various lithified morpho-structures in two hotsprings of Yellowstone National Park. These morpho-structures - flat-topped columns, columnar cones, and ridged cones - resemble ancient stromatolites, which are possibly biogenic in origin. The top, middle and bottom sections of these lithified morpho-structures, as well as surrounding non-lithified mats were analyzed to determine the vertical and spatial distribution of cyanobacterial communities. Results from DGGE indicate that the cyanobacterial community composition of lithified morpho-structures (flat-topped columns, columnar cones, and ridged cones) were largely similar in vertical distribution as well as among the morpho-structures being studied. Preliminary results indicate that the cyanobacterial communities in these lithified morpho-structures were significantly different from communities in surrounding non-lithified mats. These results provide additional support to the theory that certain Phormidium/Leptolyngbya species are involved in the morphogenesis of lithifying morpho-structures in hotsprings and may have played a role in the formation of ancient stromatolites.

Connexin 32 and connexin 43 are involved in lineage restriction of hepatic progenitor cells to hepatocytes

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Haiyun Pei

2017-11-01

Full Text Available Abstract Background Bi-potential hepatic progenitor cells can give rise to both hepatocytes and cholangiocytes, which is the last phase and critical juncture in terms of sequentially hepatic lineage restriction from any kind of stem cells. If their differentiation can be controlled, it might access to functional hepatocytes to develop pharmaceutical and biotechnology industries as well as cell therapies for end-stage liver diseases. Methods In this study, we investigated the influence of Cx32 and Cx43 on hepatocyte differentiation of WB-F344 cells by in vitro gain and loss of function analyses. An inhibitor of Cx32 was also used to make further clarification. To reveal p38 MAPK pathway is closely related to Cxs, rats with 70% partial hepatectomy were injected intraperitoneally with a p38 inhibitor, SB203580. Besides, the effects of p38 MAPK pathway on differentiation of hepatoblasts isolated from fetal rat livers were evaluated by addition of SB203580 in culture medium. Results In vitro gain and loss of function analyses showed overexpression of Connexin 32 and knockdown of Connexin 43 promoted hepatocytes differentiation from hepatic progenitor cells. In addition, in vitro and ex vivo research revealed inhibition of p38 mitogen-activated protein kinase pathway can improve hepatocytes differentiation correlating with upregulation of Connexin 32 expression and downregulation of Connexin 43 expression. Conclusions Here we demonstrate that Connexins play crucial roles in facilitating differentiation of hepatic progenitors. Our work further implicates that regulators of Connexins and their related pathways might provide new insights to improve lineage restriction of stem cells to mature hepatocytes.

Targeting of Mesenchymal Stromal Cells by Cre-Recombinase Transgenes Commonly Used to Target Osteoblast Lineage Cells.

Science.gov (United States)

Zhang, Jingzhu; Link, Daniel C

2016-11-01

The targeting specificity of tissue-specific Cre-recombinase transgenes is a key to interpreting phenotypes associated with their use. The Ocn-Cre and Dmp1-Cre transgenes are widely used to target osteoblasts and osteocytes, respectively. Here, we used high-resolution microscopy of bone sections and flow cytometry to carefully define the targeting specificity of these transgenes. These transgenes were crossed with Cxcl12 gfp mice to identify Cxcl12-abundant reticular (CAR) cells, which are a perivascular mesenchymal stromal population implicated in hematopoietic stem/progenitor cell maintenance. We show that in addition to osteoblasts, Ocn-Cre targets a majority of CAR cells and arteriolar pericytes. Surprisingly, Dmp1-Cre also targets a subset of CAR cells, in which expression of osteoblast-lineage genes is enriched. Finally, we introduce a new tissue-specific Cre-recombinase, Tagln-Cre, which efficiently targets osteoblasts, a majority of CAR cells, and both venous sinusoidal and arteriolar pericytes. These data show that Ocn-Cre and Dmp1-Cre target broader stromal cell populations than previously appreciated and may aid in the design of future studies. Moreover, these data highlight the heterogeneity of mesenchymal stromal cells in the bone marrow and provide tools to interrogate this heterogeneity. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

Cell lineage mapping of taste bud cells and keratinocytes in the mouse tongue and soft palate.

Science.gov (United States)

Okubo, Tadashi; Clark, Cheryl; Hogan, Brigid L M

2009-02-01

The epithelium of the mouse tongue and soft palate consists of at least three distinct epithelial cell populations: basal cells, keratinized cells organized into filiform and fungiform papillae, and taste receptor cells present in tight clusters known as taste buds in the fungiform and circumvallate papillae and soft palate. All three cell types develop from the simple epithelium of the embryonic tongue and palate, and are continually replaced in the adult by cell turnover. Previous studies using pulse-chase tritiated thymidine labeling in the adult mouse provided evidence for a high rate of cell turnover in the keratinocytes (5-7 days) and taste buds (10 days). However, little is known about the localization and phenotype of the long-term stem or progenitor cells that give rise to the mature taste bud cells and surrounding keratinocytes in these gustatory tissues. Here, we make use of a tamoxifen-inducible K14-CreER transgene and the ROSA26 LacZ reporter allele to lineage trace the mature keratinocytes and taste bud cells of the early postnatal and adult mouse tongue and soft palate. Our results support the hypothesis that both the pore keratinocytes and receptor cells of the taste bud are derived from a common K14(+)K5(+)Trp63(+)Sox2(+) population of bipotential progenitor cells located outside the taste bud. The results are also compatible with models in which the keratinocytes of the filiform and fungiform papillae are derived from basal progenitor cells localized at the base of these structures.

Association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of Microcoleus chthonoplastes in hypersaline cyanobacterial mats

Science.gov (United States)

D'Amelio, E. D.; Cohen, Y.; Des Marais, D. J.

1987-01-01

An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8-0.9 micrometer wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300-1200 micrometers, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur

A novel cross-satellite based assessment of the spatio-temporal development of a cyanobacterial harmful algal bloom

Science.gov (United States)

Page, Benjamin P.; Kumar, Abhishek; Mishra, Deepak R.

2018-04-01

As the frequency of cyanobacterial harmful algal blooms (CyanoHABs) become more common in recreational lakes and water supply reservoirs, demand for rapid detection and temporal monitoring will be imminent for effective management. The goal of this study was to demonstrate a novel and potentially operational cross-satellite based protocol for synoptic monitoring of rapidly evolving and increasingly common CyanoHABs in inland waters. The analysis involved a novel way to cross-calibrate a chlorophyll-a (Chl-a) detection model for the Landsat-8 OLI sensor from the relationship between the normalized difference chlorophyll index and the floating algal index derived from Sentinel-2A on a coinciding overpass date during the summer CyanoHAB bloom in Utah Lake. This aided in the construction of a time-series phenology of the Utah Lake CyanoHAB event. Spatio-temporal cyanobacterial density maps from both Sentinel-2A and Landsat-8 sensors revealed that the bloom started in the first week of July 2016 (July 3rd, mean cell count: 9163 cells/mL), reached peak in mid-July (July 15th, mean cell count: 108176 cells/mL), and reduced in August (August 24th, mean cell count: 9145 cells/mL). Analysis of physical and meteorological factors suggested a complex interaction between landscape processes (high surface runoff), climatic conditions (high temperature, high rainfall followed by negligible rainfall, stable wind), and water quality (low water level, high Chl-a) which created a supportive environment for triggering these blooms in Utah Lake. This cross satellite-based monitoring methods can be a great tool for regular monitoring and will reduce the budget cost for monitoring and predicting CyanoHABs in large lakes.

Chromatin dynamics in Pollen Mother Cells underpin a common scenario at the somatic-to-reproductive fate transition of both the male and female lineages in Arabidopsis

Directory of Open Access Journals (Sweden)

Wenjing eShe

2015-04-01

Full Text Available Unlike animals, where the germline is established early during embryogenesis, plants set aside their reproductive lineage late in development in dedicated floral organs. The specification of pollen mother cells (PMCs committed to meiosis takes place in the sporogenous tissue in anther locules and marks the somatic-to-reproductive cell fate transition towards the male reproductive lineage. Here we show that Arabidopsis PMCs differentiation is accompanied by large-scale changes in chromatin organization. This is characterized by significant increase in nuclear volume, chromatin decondensation, reduction in heterochromatin, eviction of linker histones and the H2AZ histone variant. These structural alterations are accompanied by dramatic, quantitative changes in histone modifications levels compared to that of surrounding somatic cells that do not share a sporogenic fate. All these changes are highly reminiscent of those we have formerly described in female megaspore mother cells (MMCs. This indicates that chromatin reprogramming is a common underlying scenario in the somatic-to-reproductive cell fate transition in both male and female lineages.

Towards comprehensive cell lineage reconstructions in complex organisms using light-sheet microscopy.

Science.gov (United States)

Amat, Fernando; Keller, Philipp J

2013-05-01

Understanding the development of complex multicellular organisms as a function of the underlying cell behavior is one of the most fundamental goals of developmental biology. The ability to quantitatively follow cell dynamics in entire developing embryos is an indispensable step towards such a system-level understanding. In recent years, light-sheet fluorescence microscopy has emerged as a particularly promising strategy for recording the in vivo data required to realize this goal. Using light-sheet fluorescence microscopy, entire complex organisms can be rapidly imaged in three dimensions at sub-cellular resolution, achieving high temporal sampling and excellent signal-to-noise ratio without damaging the living specimen or bleaching fluorescent markers. The resulting datasets allow following individual cells in vertebrate and higher invertebrate embryos over up to several days of development. However, the complexity and size of these multi-terabyte recordings typically preclude comprehensive manual analyses. Thus, new computational approaches are required to automatically segment cell morphologies, accurately track cell identities and systematically analyze cell behavior throughout embryonic development. We review current efforts in light-sheet microscopy and bioimage informatics towards this goal, and argue that comprehensive cell lineage reconstructions are finally within reach for many key model organisms, including fruit fly, zebrafish and mouse. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

Nutrient control of cyanobacterial blooms in the Baltic Sea

NARCIS (Netherlands)

Stal, L.J.; Staal, M.J.; Villbrandt, M.

1999-01-01

Cyanobacterial blooms in the Baltic Sea were investigated with respect to growth Limitation and nitrogen fixation. The community was composed predominantly of Synechococcus spp., and large, heterocystous, nitrogen-fixing cyanobacteria (Aphanizomenon spp, and Nodularia spp.), that usually formed

Photoautotrophic Polyhydroxybutyrate Granule Formation Is Regulated by Cyanobacterial Phasin PhaP in Synechocystis sp. Strain PCC 6803

Science.gov (United States)

Hauf, Waldemar; Watzer, Björn; Roos, Nora; Klotz, Alexander

2015-01-01

Cyanobacteria are photoautotrophic microorganisms which fix atmospheric carbon dioxide via the Calvin-Benson cycle to produce carbon backbones for primary metabolism. Fixed carbon can also be stored as intracellular glycogen, and in some cyanobacterial species like Synechocystis sp. strain PCC 6803, polyhydroxybutyrate (PHB) accumulates when major nutrients like phosphorus or nitrogen are absent. So far only three enzymes which participate in PHB metabolism have been identified in this organism, namely, PhaA, PhaB, and the heterodimeric PHB synthase PhaEC. In this work, we describe the cyanobacterial PHA surface-coating protein (phasin), which we term PhaP, encoded by ssl2501. Translational fusion of Ssl2501 with enhanced green fluorescent protein (eGFP) showed a clear colocalization to PHB granules. A deletion of ssl2501 reduced the number of PHB granules per cell, whereas the mean PHB granule size increased as expected for a typical phasin. Although deletion of ssl2501 had almost no effect on the amount of PHB, the biosynthetic activity of PHB synthase was negatively affected. Secondary-structure prediction and circular dichroism (CD) spectroscopy of PhaP revealed that the protein consists of two α-helices, both of them associating with PHB granules. Purified PhaP forms oligomeric structures in solution, and both α-helices of PhaP contribute to oligomerization. Together, these results support the idea that Ssl2501 encodes a cyanobacterial phasin, PhaP, which regulates the surface-to-volume ratio of PHB granules. PMID:25911471

Replacement of Lost Lgr5-Positive Stem Cells through Plasticity of Their Enterocyte-Lineage Daughters.

Science.gov (United States)

Tetteh, Paul W; Basak, Onur; Farin, Henner F; Wiebrands, Kay; Kretzschmar, Kai; Begthel, Harry; van den Born, Maaike; Korving, Jeroen; de Sauvage, Frederic; van Es, Johan H; van Oudenaarden, Alexander; Clevers, Hans

2016-02-04

Intestinal crypts display robust regeneration upon injury. The relatively rare secretory precursors can replace lost stem cells, but it is unknown if the abundant enterocyte progenitors that express the Alkaline phosphate intestinal (Alpi) gene also have this capacity. We created an Alpi-IRES-CreERT2 (Alpi(CreER)) knockin allele for lineage tracing. Marked clones consist entirely of enterocytes and are all lost from villus tips within days. Genetic fate-mapping of Alpi(+) cells before or during targeted ablation of Lgr5-expressing stem cells generated numerous long-lived crypt-villus "ribbons," indicative of dedifferentiation of enterocyte precursors into Lgr5(+) stems. By single-cell analysis of dedifferentiating enterocytes, we observed the generation of Paneth-like cells and proliferative stem cells. We conclude that the highly proliferative, short-lived enterocyte precursors serve as a large reservoir of potential stem cells during crypt regeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

Cyanobacterial populations in biological soil crusts of the northwest Negev Desert, Israel - effects of local conditions and disturbance.

Science.gov (United States)

Hagemann, Martin; Henneberg, Manja; Felde, Vincent J M N L; Berkowicz, Simon M; Raanan, Hagai; Pade, Nadin; Felix-Henningsen, Peter; Kaplan, Aaron

2016-11-02

Biological soil crusts (BSCs) fulfill numerous ecological functions in arid and semiarid areas. Cyanobacteria are important BSC organisms, which are responsible for carbon fixation, N 2 -fixation, and binding of soil via extracellular polysaccharides. The cyanobacterial populations were characterized in different sampling plots established in three experimental stations along a rainfall gradient within NW Negev Desert, Israel. Cyanobacterial crust thickness and osmolyte accumulation therein decreased in plots with lower moisture. The cyanobacterial population structure also changed in different plots. We observed an increase of subsection III cyanobacteria such as Microcoleus spp. and Leptolyngbya sp. and a decreasing proportion of strains belonging to subsections I and IV in drier areas on the rainfall gradient. This population shift was also observed in the sampling plots, which were situated at various relief positions within the sand dune experimental sites. We also characterized the cyanobacterial populations within mechanically disturbed plots. After four years, they reached between 80 and 50% of the control populations in the northern-most and southern stations, respectively. Our results suggest that the cyanobacterial population is sensitive not only to macroscale factors but may also be subject to local climate variations and that four years were insufficient for complete recovery of the cyanobacterial population. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cyanobacterial composition of microbial mats from an Australian thermal spring: a polyphasic evaluation.

Science.gov (United States)

McGregor, Glenn B; Rasmussen, J Paul

2008-01-01

Cyanobacterial composition of microbial mats from an alkaline thermal spring issuing at 43-71 degrees C from tropical north-eastern Australia are described using a polyphasic approach. Eight genera and 10 species from three cyanobacterial orders were identified based on morphological characters. These represented taxa previously known as thermophilic from other continents. Ultrastructural analysis of the tower mats revealed two filamentous morphotypes contributed the majority of the biomass. Both types had ultrastructural characteristics of the family Pseudanabaenaceae. DNA extracts were made from sections of the tentaculiform towers and the microbial community analysed by 16S cyanobacteria-specific PCR and denaturing-gradient gel electrophoresis. Five significant bands were identified and sequenced. Two bands clustered closely with Oscillatoria amphigranulata isolated from New Zealand hot springs; one unique phylotype had only moderate similarity to a range of Leptolyngbya species; and one phylotype was closely related to a number of Geitlerinema species. Generally the approaches yielded complementary information, however the results suggest that species designation based on morphological and ultrastructural criteria alone often fails to recognize their true phylogenetic position. Conversely some molecular techniques may fail to detect rare taxa suggesting that the widest possible suite of techniques be applied when conducting analyses of cyanobacterial diversity of natural populations. This is the first polyphasic evaluation of thermophilic cyanobacterial communities from the Australian continent.

Changes in keratin 8/18 expression in human granulosa cell lineage are associated to cell death/survival events: potential implications for the maintenance of the ovarian reserve.

Science.gov (United States)

Gaytan, F; Morales, C; Roa, J; Tena-Sempere, M

2018-04-01

Is keratin 8/18 (K8/K18) expression linked to cell death/survival events in the human granulosa cell lineage? A close association exists between changes in K8/K18 expression and cell death/survival events along the human granulosa cell lineage lifespan. In addition to their structural and mechanical functions, K8/K18 play essential roles regulating cell death, survival and differentiation in several non-gonadal epithelial tissues. Transfection of the granulosa-like tumor KGN cells with siRNA to interfere KRT8 and KRT18 expression increases FAS-mediated apoptosis, while an inverse association between K8/K18 expression and cell death has been found in the bovine antral follicles and corpus luteum. Yet, only fragmentary and inconclusive information exists regarding K8/K18 expression in the human ovary. Expression of K8/K18 was assessed by immunohistochemistry at different stages of the granulosa cell lineage, from flattened granulosa cells in primordial follicles to fully luteinized granulosa-lutein cells in the corpus luteum (including corpus luteum of pregnancy). Immunohistochemical detection of K8/K18 was conducted in 40 archival ovarian samples from women aged 17-39 years. K8/K18 expression was analyzed at the different stages of follicle development and corpus luteum lifespan. The proportions of primordial follicles showing all K8/K18-positive, all K8/K18 negative, or a mixture of K8/K18 negative and positive granulosa cells were quantified in 18 ovaries, divided into three age groups: ≤ 25 years (N = 6), 26-30 (N = 6) and 31-36 (N = 6) years. A total number of 1793 primordial, 750 transitional and 140 primary follicles were scored. A close association was found between changes in K8/K18 expression and cell death/cell survival events in the human granulosa cell lineage. Large secondary and early antral follicles (most of them undergoing atresia) and regressing corpora lutea displayed low/absent K8/K18 expression. Conversely, early growing and some large antral

Mesoderm Lineage 3D Tissue Constructs Are Produced at Large-Scale in a 3D Stem Cell Bioprocess.

Science.gov (United States)

Cha, Jae Min; Mantalaris, Athanasios; Jung, Sunyoung; Ji, Yurim; Bang, Oh Young; Bae, Hojae

2017-09-01

Various studies have presented different approaches to direct pluripotent stem cell differentiation such as applying defined sets of exogenous biochemical signals and genetic/epigenetic modifications. Although differentiation to target lineages can be successfully regulated, such conventional methods are often complicated, laborious, and not cost-effective to be employed to the large-scale production of 3D stem cell-based tissue constructs. A 3D-culture platform that could realize the large-scale production of mesoderm lineage tissue constructs from embryonic stem cells (ESCs) is developed. ESCs are cultured using our previously established 3D-bioprocess platform which is amenable to mass-production of 3D ESC-based tissue constructs. Hepatocarcinoma cell line conditioned medium is introduced to the large-scale 3D culture to provide a specific biomolecular microenvironment to mimic in vivo mesoderm formation process. After 5 days of spontaneous differentiation period, the resulting 3D tissue constructs are composed of multipotent mesodermal progenitor cells verified by gene and molecular expression profiles. Subsequently the optimal time points to trigger terminal differentiation towards cardiomyogenesis or osteogenesis from the mesodermal tissue constructs is found. A simple and affordable 3D ESC-bioprocess that can reach the scalable production of mesoderm origin tissues with significantly improved correspondent tissue properties is demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast and scalable inference of multi-sample cancer lineages.

KAUST Repository

Popic, Victoria; Salari, Raheleh; Hajirasouliha, Iman; Kashef-Haghighi, Dorna; West, Robert B; Batzoglou, Serafim

2015-01-01

Somatic variants can be used as lineage markers for the phylogenetic reconstruction of cancer evolution. Since somatic phylogenetics is complicated by sample heterogeneity, novel specialized tree-building methods are required for cancer phylogeny reconstruction. We present LICHeE (Lineage Inference for Cancer Heterogeneity and Evolution), a novel method that automates the phylogenetic inference of cancer progression from multiple somatic samples. LICHeE uses variant allele frequencies of somatic single nucleotide variants obtained by deep sequencing to reconstruct multi-sample cell lineage trees and infer the subclonal composition of the samples. LICHeE is open source and available at http://viq854.github.io/lichee .

Fast and scalable inference of multi-sample cancer lineages.

KAUST Repository

Popic, Victoria

2015-05-06

Somatic variants can be used as lineage markers for the phylogenetic reconstruction of cancer evolution. Since somatic phylogenetics is complicated by sample heterogeneity, novel specialized tree-building methods are required for cancer phylogeny reconstruction. We present LICHeE (Lineage Inference for Cancer Heterogeneity and Evolution), a novel method that automates the phylogenetic inference of cancer progression from multiple somatic samples. LICHeE uses variant allele frequencies of somatic single nucleotide variants obtained by deep sequencing to reconstruct multi-sample cell lineage trees and infer the subclonal composition of the samples. LICHeE is open source and available at http://viq854.github.io/lichee .

Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

Science.gov (United States)

Alchin, Bruce; Williams, Wendy

2015-04-01

In arid and semi-arid Australia, the central role of healthy soil ecosystems in broad-acre grazing lands may be attributed to the widespread presence of cyanobacterial crusts. In terms of soil nutrient cycling and stability their role is particularly crucial in a climate dominated by annual dry seasons and variable wet seasons. In this study, we aimed to measure the contribution of cyanobacteria to soil nutrient cycling under contrasting levels of disturbance associated with grazing management. Field sampling was carried out on six paired sites (twelve properties) located across an east-west 3,000 km transect that covered different rangeland types on grazing properties in northern Australia (Queensland, Northern Territory and Western Australia). At each location paired sites were established and two different management systems were assessed, cell-paddock rotations (25-400 ha) and continuous grazing (200-2,000 ha). Cyanobacterial soil crusts were recorded from all of the twelve sites and cyanobacteria with the capacity to fix nitrogen were found at ten of the twelve sites. The overall diversity of cyanobacteria varied from three to ten species under any type of grazing system. As field work was conducted in the dry season, it is likely that the diversity may be greater in the wet season than the initial data may indicate. The average cyanobacterial soil crust cover across soil surfaces, between grass tussocks, during the dry season was estimated to be 50.9% and, 42.6% in the early wet season. This reflected longer established crust cover (dry season) versus newly established crusts. There was a high level of variability in the biomass of cyanobacteria however; the grazing system did not have any marked effect on the biomass for any one rangeland type. The grazing system differences did not appear to significantly influence the diversity at any location except on a floodplain in the Pilbara (WA). Biological nitrogen fixation by cyanobacteria was recorded at all

5-Hydroxymethylcytosine Remodeling Precedes Lineage Specification during Differentiation of Human CD4+ T Cells

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Colm E. Nestor

2016-07-01

Full Text Available 5-methylcytosine (5mC is converted to 5-hydroxymethylcytosine (5hmC by the TET family of enzymes as part of a recently discovered active DNA de-methylation pathway. 5hmC plays important roles in regulation of gene expression and differentiation and has been implicated in T cell malignancies and autoimmunity. Here, we report early and widespread 5mC/5hmC remodeling during human CD4+ T cell differentiation ex vivo at genes and cell-specific enhancers with known T cell function. We observe similar DNA de-methylation in CD4+ memory T cells in vivo, indicating that early remodeling events persist long term in differentiated cells. Underscoring their important function, 5hmC loci were highly enriched for genetic variants associated with T cell diseases and T-cell-specific chromosomal interactions. Extensive functional validation of 22 risk variants revealed potentially pathogenic mechanisms in diabetes and multiple sclerosis. Our results support 5hmC-mediated DNA de-methylation as a key component of CD4+ T cell biology in humans, with important implications for gene regulation and lineage commitment.

Spatio-temporal re-organization of replication foci accompanies replication domain consolidation during human pluripotent stem cell lineage specification

Science.gov (United States)

Wilson, Korey A.; Elefanty, Andrew G.; Stanley, Edouard G.; Gilbert, David M.

2016-01-01

ABSTRACT Lineage specification of both mouse and human pluripotent stem cells (PSCs) is accompanied by spatial consolidation of chromosome domains and temporal consolidation of their replication timing. Replication timing and chromatin organization are both established during G1 phase at the timing decision point (TDP). Here, we have developed live cell imaging tools to track spatio-temporal replication domain consolidation during differentiation. First, we demonstrate that the fluorescence ubiquitination cell cycle indicator (Fucci) system is incapable of demarcating G1/S or G2/M cell cycle transitions. Instead, we employ a combination of fluorescent PCNA to monitor S phase progression, cytokinesis to demarcate mitosis, and fluorescent nucleotides to label early and late replication foci and track their 3D organization into sub-nuclear chromatin compartments throughout all cell cycle transitions. We find that, as human PSCs differentiate, the length of S phase devoted to replication of spatially clustered replication foci increases, coincident with global compartmentalization of domains into temporally clustered blocks of chromatin. Importantly, re-localization and anchorage of domains was completed prior to the onset of S phase, even in the context of an abbreviated PSC G1 phase. This approach can also be employed to investigate cell fate transitions in single PSCs, which could be seen to differentiate preferentially from G1 phase. Together, our results establish real-time, live-cell imaging methods for tracking cell cycle transitions during human PSC differentiation that can be applied to study chromosome domain consolidation and other aspects of lineage specification. PMID:27433885

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

NARCIS (Netherlands)

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma; Cillero-Castro, Carmen; Budzyńska, Agnieszka; Goldyn, Ryszard; Kozak, Anna; Rosińska, Joanna; Szeląg-Wasielewska, Elżbieta; Domek, Piotr; Jakubowska-Krepska, Natalia; Kwasizur, Kinga; Messyasz, Beata; Pełechaty, Aleksandra; Pełechaty, Mariusz; Kokocinski, Mikolaj; García-Murcia, Ana; Real, Monserrat; Romans, Elvira; Noguero-Ribes, Jordi; Duque, David Parreño; Fernández-Morán, Elísabeth; Karakaya, Nusret; Häggqvist, Kerstin; Demir, Nilsun; Beklioğlu, Meryem; Filiz, Nur; Levi, Eti E.; Iskin, Uğur; Bezirci, Gizem; Tavşanoğlu, Ülkü Nihan; Özhan, Koray; Gkelis, Spyros; Panou, Manthos; Fakioglu, Özden; Avagianos, Christos; Kaloudis, Triantafyllos; Çelik, Kemal; Yilmaz, Mete; Marcé, Rafael; Catalán, Nuria; Bravo, Andrea G.; Buck, Moritz; Colom-Montero, William; Mustonen, Kristiina; Pierson, Don; Yang, Yang; Raposeiro, Pedro M.; Gonçalves, Vítor; Antoniou, Maria G.; Tsiarta, Nikoletta; McCarthy, Valerie; Perello, Victor C.; Feldmann, Tõnu; Laas, Alo; Panksep, Kristel; Tuvikene, Lea; Gagala, Ilona; Mankiewicz-Boczek, Joana; Yağcı, Meral Apaydın; Çınar, Şakir; Çapkın, Kadir; Yağcı, Abdulkadir; Cesur, Mehmet; Bilgin, Fuat; Bulut, Cafer; Uysal, Rahmi; Obertegger, Ulrike; Boscaini, Adriano; Flaim, Giovanna; Salmaso, Nico; Cerasino, Leonardo; Richardson, Jessica; Visser, Petra M; Verspagen, Jolanda M. H.; Karan, Tünay; Soylu, Elif Neyran; Maraşlıoğlu, Faruk; Napiórkowska-Krzebietke, Agnieszka; Ochocka, Agnieszka; Pasztaleniec, Agnieszka; Antão-Geraldes, Ana M.; Vasconcelos, Vitor; Morais, João; Vale, Micaela; Köker, Latife; Akçaalan, Reyhan; Albay, Meriç; Špoljarić Maronić, Dubravka; Stević, Filip; Žuna Pfeiffer, Tanja; Fonvielle, Jeremy; Straile, Dietmar; Rothhaupt, Karl-Otto; Hansson, Lars-Anders; Urrutia-Cordero, Pablo; Bláha, Luděk; Geriš, Rodan; Fránková, Markéta; Koçer, Mehmet Ali Turan; Alp, Mehmet Tahir; Remec-Rekar, Spela; Elersek, Tina; Triantis, Theodoros; Zervou, Sevasti-Kiriaki; Hiskia, Anastasia; Haande, Sigrid; Skjelbred, Birger; Madrecka, Beata; Nemova, Hana; Drastichova, Iveta; Chomova, Lucia; Edwards, Christine; Sevindik, Tuğba Ongun; Tunca, Hatice; Önem, Burçin; Aleksovski, Boris; Krstić, Svetislav; Vucelić, Itana Bokan; Nawrocka, Lidia; Salmi, Pauliina; Machado-Vieira, Danielle; de Oliveira, Alinne Gurjão; Delgado-Martín, Jordi; García-García, David; Cereijo, Jose Luís; Gomà, Joan; Trapote, Mari Carmen; Vegas-Vilarrúbia, Teresa; Obrador, Biel; Grabowska, Magdalena; Karpowicz, Maciej; Chmura, Damian; Úbeda, Bárbara; Gálvez, José Ángel; Özen, Arda; Christoffersen, Kirsten Seestern; Warming, Trine Perlt; Kobos, Justyna; Mazur-Marzec, Hanna; Pérez-Martínez, Carmen; Ramos-Rodríguez, Eloísa; Arvola, Lauri; Alcaraz-Párraga, Pablo; Toporowska, Magdalena; Pawlik-Skowronska, Barbara; Niedźwiecki, Michał; Pęczuła, Wojciech; Leira, Manel; Hernández, Armand; Moreno-Ostos, Enrique; Blanco, José María; Rodríguez, Valeriano; Montes-Pérez, Jorge Juan; Palomino, Roberto L.; Rodríguez-Pérez, Estela; Carballeira, Rafael; Camacho, Antonio; Picazo, Antonio; Rochera, Carlos; Santamans, Anna C.; Ferriol, Carmen; Romo, Susana; Soria, Juan Miguel; Dunalska, Julita; Sieńska, Justyna; Szymański, Daniel; Kruk, Marek; Kostrzewska-Szlakowska, Iwona; Jasser, Iwona; Žutinić, Petar; Gligora Udovič, Marija; Plenković-Moraj, Anđelka; Frąk, Magdalena; Bańkowska-Sobczak, Agnieszka; Wasilewicz, Michał; Özkan, Korhan; Maliaka, Valentini; Kangro, Kersti; Grossart, Hans-Peter; Paerl, Hans W.; Carey, Cayelan C.; Ibelings, Bas W.

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and

The presence of the cyanobacterial toxin microcystin in black band disease of corals.

Science.gov (United States)

Richardson, Laurie L; Sekar, Raju; Myers, Jamie L; Gantar, Miroslav; Voss, Joshua D; Kaczmarsky, Longin; Remily, Elizabeth R; Boyer, Gregory L; Zimba, Paul V

2007-07-01

Black band disease (BBD) is a migrating, cyanobacterial dominated, sulfide-rich microbial mat that moves across coral colonies lysing coral tissue. While it is known that BBD sulfate-reducing bacteria contribute to BBD pathogenicity by production of sulfide, additional mechanisms of toxicity may be involved. Using HPLC/MS, the cyanotoxin microcystin was detected in 22 field samples of BBD collected from five coral species on nine reefs of the wider Caribbean (Florida Keys and Bahamas). Two cyanobacterial cultures isolated from BBD, Geitlerinema and Leptolyngbya sp. contained microcystin based on HPLC/MS, with toxic activity confirmed using the protein phosphatase inhibition assay. The gene mcyA from the microcystin synthesis complex was detected in two field samples and from both BBD cyanobacterial cultures. Microcystin was not detected in six BBD samples from a different area of the Caribbean (St Croix, USVI) and the Philippines, suggesting regional specificity for BBD microcystin. This is the first report of the presence of microcystin in a coral disease.

Production of anatoxin-a by cyanobacterial strains isolated from Portuguese fresh water systems.

Science.gov (United States)

Osswald, Joana; Rellán, Sandra; Gago-Martinez, Ana; Vasconcelos, Vítor

2009-11-01

The occurrence of anatoxin-a in several freshwater systems in Portugal and its production by Portuguese cyanobacterial strains, after cultivation in laboratory, were studied. Surface water samples from 9 water bodies, for recreational and human consumption usage, were surveyed for anatoxin-a presence and for obtaining cultures of pure cyanobacterial strains. Anatoxin-a analysis was performed by high performance liquid chromatography (HPLC) with fluorescence detection (FLD) followed by Mass Spectrometry (MS) confirmation. No anatoxin-a was detected in all the natural water samples (limit of detection (LOD) = 25 ng l(-1)) but among the 22 isolated cyanobacterial strains, 13 could produce anatoxin-a in laboratory conditions (LOD = 3 ng g(-1) dw). This proportion of anatoxin-a producing strains (59.1%) in laboratory is discussed considering the hypothesis that anatoxin-a is a more frequent metabolite in cyanobacteria than it was thought before and making its occurrence in Portuguese freshwaters almost certain. Therefore, health and ecological risks caused by anatoxin-a in Portugal, should be seriously considered.

Controls on O2 Production in Cyanobacterial Mats and Implications for Earth's Oxygenation

Science.gov (United States)

Dick, Gregory J.; Grim, Sharon L.; Klatt, Judith M.

2018-05-01

Cyanobacterial mats are widely assumed to have been globally significant hot spots of biogeochemistry and evolution during the Archean and Proterozoic, but little is known about their quantitative contributions to global primary productivity or Earth's oxygenation. Modern systems show that mat biogeochemistry is the outcome of concerted activities and intimate interactions between various microbial metabolisms. Emerging knowledge of the regulation of oxygenic and sulfide-driven anoxygenic photosynthesis by versatile cyanobacteria, and their interactions with sulfur-oxidizing bacteria and sulfate-reducing bacteria, highlights how ecological and geochemical processes can control O2 production in cyanobacterial mats in unexpected ways. This review explores such biological controls on O2 production. We argue that the intertwined effects of light availability, redox geochemistry, regulation and competition of microbial metabolisms, and biogeochemical feedbacks result in emergent properties of cyanobacterial mat communities that are all critical yet largely overlooked mechanisms to potentially explain the protracted nature of Earth's oxygenation.

Cellular responses in the cyanobacterial symbiont during its vertical transfer between plant generations in the Azolla microphylla symbiosis.

Science.gov (United States)

Zheng, Weiwen; Bergman, Birgitta; Chen, Bin; Zheng, Siping; Guan, Xiong; Xiang, Guan; Rasmussen, Ulla

2009-01-01

The nitrogen-fixing symbiosis between cyanobacteria and the water fern Azolla microphylla is, in contrast to other cyanobacteria-plant symbioses, the only one of a perpetual nature. The cyanobacterium is vertically transmitted between the plant generations, via vegetative fragmentation of the host or sexually within megasporocarps. In the latter process, subsets of the cyanobacterial population living endophytically in the Azolla leaves function as inocula for the new plant generations. Using electron microscopy and immunogold-labeling, the fate of the cyanobacterium during colonization and development of the megasporocarp was revealed. On entering the indusium chamber of the megasporocarps as small-celled motile cyanobacterial filaments (hormogonia), these differentiated into large thick-walled akinetes (spores) in a synchronized manner. This process was accompanied by cytoplasmic reorganizations and the release of numerous membrane vesicles, most of which contained DNA, and the formation of a highly structured biofilm. Taken together the data revealed complex adaptations in the cyanobacterium during its transition between plant generations.

Chloroplast two-component systems: evolution of the link between photosynthesis and gene expression.

Science.gov (United States)

Puthiyaveetil, Sujith; Allen, John F

2009-06-22

Two-component signal transduction, consisting of sensor kinases and response regulators, is the predominant signalling mechanism in bacteria. This signalling system originated in prokaryotes and has spread throughout the eukaryotic domain of life through endosymbiotic, lateral gene transfer from the bacterial ancestors and early evolutionary precursors of eukaryotic, cytoplasmic, bioenergetic organelles-chloroplasts and mitochondria. Until recently, it was thought that two-component systems inherited from an ancestral cyanobacterial symbiont are no longer present in chloroplasts. Recent research now shows that two-component systems have survived in chloroplasts as products of both chloroplast and nuclear genes. Comparative genomic analysis of photosynthetic eukaryotes shows a lineage-specific distribution of chloroplast two-component systems. The components and the systems they comprise have homologues in extant cyanobacterial lineages, indicating their ancient cyanobacterial origin. Sequence and functional characteristics of chloroplast two-component systems point to their fundamental role in linking photosynthesis with gene expression. We propose that two-component systems provide a coupling between photosynthesis and gene expression that serves to retain genes in chloroplasts, thus providing the basis of cytoplasmic, non-Mendelian inheritance of plastid-associated characters. We discuss the role of this coupling in the chronobiology of cells and in the dialogue between nuclear and cytoplasmic genetic systems.

Use of Ion-Channel Modulating Agents to Study Cyanobacterial Na+ - K+ Fluxes

Directory of Open Access Journals (Sweden)

Pomati Francesco

2004-01-01

Full Text Available Here we describe an experimental design aimed to investigate changes in total cellular levels of Na+ and K+ ions in cultures of freshwater filamentous cyanobacteria. Ion concentrations were measured in whole cells by flame photometry. Cellular Na+ levels increased exponentially with rising alkalinity, with K+ levels being maximal for optimal growth pH (~8. At standardized pH conditions, the increase in cellular Na+, as induced by NaCl at 10 mM, was coupled by the two sodium channel-modulating agents lidocaine hydrochloride at 1 &mgr;M and veratridine at 100 &mgr;M. Both the channel-blockers amiloride (1 mM and saxitoxin (1 &mgr;M, decreased cell-bound Na+ and K+ levels. Results presented demonstrate the robustness of well-defined channel blockers and channel-activators in the study of cyanobacterial Na+- K+ fluxes.

Rapid development of cyanobacterial crust in the field for combating desertification.

Science.gov (United States)

Park, Chan-Ho; Li, Xin Rong; Zhao, Yang; Jia, Rong Liang; Hur, Jae-Seoun

2017-01-01

Desertification is currently a major concern, and vast regions have already been devastated in the arid zones of many countries. Combined application of cyanobacteria with soil fixing chemicals is a novel method of restoring desertified areas. Three cyanobacteria, Nostoc sp. Vaucher ex Bornet & Flahault, Phormidium sp. Kützing ex Gomont and Scytonema arcangeli Bornet ex Flahault were isolated and tested in this study. Tacki-SprayTM (TKS7), which consists of bio-polysaccharides and tackifiers, was used as a soil fixing agent. In addition, superabsorbent polymer (SAP) was applied to the soil as a water-holding material and nutrient supplement. Application of cyanobacteria with superabsorbent polymer and TKS7 (CST) remarkably improved macro-aggregate stability against water and erodibility against wind after 12 months of inoculation when compared to the control soil. The mean weight diameter and threshold friction velocity of the CST treated soil were found to be 75% and 88% of those of the approximately 20-year-old natural cyanobacterial crust (N-BSC), respectively, while these values were 68% and 73% of those of the N-BSC soil after a single treatment of cyanobacteria alone (CY). Interestingly, biological activities of CST were similar to those of CY. Total carbohydrate contents, cyanobacterial biomass, microbial biomass, soil respiration, carbon fixation and effective quantum yield of CST treated soil were enhanced by 50-100% of the N-BSC, while those of control soil were negligible. Our results suggest that combined application of cyanobacteria with soil fixing chemicals can rapidly develop cyanobacterial crust formation in the field within 12 months. The physical properties and biological activities of the inoculated cyanobacterial crust were stable during the study period. The novel method presented herein serves as another approach for combating desertification in arid regions.

Rapid development of cyanobacterial crust in the field for combating desertification.

Directory of Open Access Journals (Sweden)

Chan-Ho Park

Full Text Available Desertification is currently a major concern, and vast regions have already been devastated in the arid zones of many countries. Combined application of cyanobacteria with soil fixing chemicals is a novel method of restoring desertified areas. Three cyanobacteria, Nostoc sp. Vaucher ex Bornet & Flahault, Phormidium sp. Kützing ex Gomont and Scytonema arcangeli Bornet ex Flahault were isolated and tested in this study. Tacki-SprayTM (TKS7, which consists of bio-polysaccharides and tackifiers, was used as a soil fixing agent. In addition, superabsorbent polymer (SAP was applied to the soil as a water-holding material and nutrient supplement. Application of cyanobacteria with superabsorbent polymer and TKS7 (CST remarkably improved macro-aggregate stability against water and erodibility against wind after 12 months of inoculation when compared to the control soil. The mean weight diameter and threshold friction velocity of the CST treated soil were found to be 75% and 88% of those of the approximately 20-year-old natural cyanobacterial crust (N-BSC, respectively, while these values were 68% and 73% of those of the N-BSC soil after a single treatment of cyanobacteria alone (CY. Interestingly, biological activities of CST were similar to those of CY. Total carbohydrate contents, cyanobacterial biomass, microbial biomass, soil respiration, carbon fixation and effective quantum yield of CST treated soil were enhanced by 50-100% of the N-BSC, while those of control soil were negligible. Our results suggest that combined application of cyanobacteria with soil fixing chemicals can rapidly develop cyanobacterial crust formation in the field within 12 months. The physical properties and biological activities of the inoculated cyanobacterial crust were stable during the study period. The novel method presented herein serves as another approach for combating desertification in arid regions.

The Mediator complex: a master coordinator of transcription and cell lineage development.

Science.gov (United States)

Yin, Jing-wen; Wang, Gang

2014-03-01

Mediator is a multiprotein complex that is required for gene transcription by RNA polymerase II. Multiple subunits of the complex show specificity in relaying information from signals and transcription factors to the RNA polymerase II machinery, thus enabling control of the expression of specific genes. Recent studies have also provided novel mechanistic insights into the roles of Mediator in epigenetic regulation, transcriptional elongation, termination, mRNA processing, noncoding RNA activation and super enhancer formation. Based on these specific roles in gene regulation, Mediator has emerged as a master coordinator of development and cell lineage determination. Here, we describe the most recent advances in understanding the mechanisms of Mediator function, with an emphasis on its role during development and disease.

Lineage tracing of genome-edited alleles reveals high fidelity axolotl limb regeneration.

Science.gov (United States)

Flowers, Grant Parker; Sanor, Lucas D; Crews, Craig M

2017-09-16

Salamanders are unparalleled among tetrapods in their ability to regenerate many structures, including entire limbs, and the study of this ability may provide insights into human regenerative therapies. The complex structure of the limb poses challenges to the investigation of the cellular and molecular basis of its regeneration. Using CRISPR/Cas, we genetically labelled unique cell lineages within the developing axolotl embryo and tracked the frequency of each lineage within amputated and fully regenerated limbs. This allowed us, for the first time, to assess the contributions of multiple low frequency cell lineages to the regenerating limb at once. Our comparisons reveal that regenerated limbs are high fidelity replicas of the originals even after repeated amputations.

Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland

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Touzet, N., E-mail: touzet.nicolas@itsligo.ie [Centre for Environmental Research, Innovation and Sustainability, School of Science, Department of Environmental Science, Institute of Technology Sligo, Sligo (Ireland); McCarthy, D.; Gill, A.; Fleming, G.T.A. [Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway (Ireland)

2016-05-15

The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies. - Highlights: • DGGE highlighted

Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland

International Nuclear Information System (INIS)

Touzet, N.; McCarthy, D.; Gill, A.; Fleming, G.T.A.

2016-01-01

The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies. - Highlights: • DGGE highlighted

Differentiation of a medulloblastoma cell line towards an astrocytic lineage using the human T lymphotropic retrovirus-1.

Science.gov (United States)

Giraudon, P; Dufay, N; Hardin, H; Reboul, A; Tardy, M; Belin, M F

1993-02-01

Constituent cells of medulloblastoma, the most common brain tumor occurring in childhood, resemble the primitive neuroepithelial cells normally found in the developing nervous system. However, mutational events prevent their further differentiation. We used the human T cell lymphotrophic virus type 1 to activate these deregulated immature cells by means of its transactivating protein Tax. Concomitant with viral infection was a decrease in cell proliferation characterized by inhibition of [3H]thymidine incorporation and in the number of cells in the G2/M phase of the cell cycle. Morphological changes suggested that medulloblastoma cells differentiated along the astrocytic lineage. The glial phenotype was confirmed by the induction of the glial fibrillary acidic protein and the glial enzyme glutamine synthetase. A direct viral effect and/or secondary effects to viral infection via paracrine/autocrine pathways could counterbalance the maturational defect in these medulloblastoma cells.

Chlorophyll f distribution and dynamics in cyanobacterial beachrock biofilms.

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Trampe, Erik; Kühl, Michael

2016-12-01

Chlorophyll (Chl) f, the most far-red (720-740 nm) absorbing Chl species, was discovered in cyanobacterial isolates from stromatolites and subsequently in other habitats as well. However, the spatial distribution and temporal dynamics of Chl f in a natural habitat have so far not been documented. Here, we report the presence of Chl f in cyanobacterial beachrock biofilms. Hyperspectral imaging on cross-sections of beachrock from Heron Island (Great Barrier Reef, Australia), showed a strong and widely distributed signature of Chl f absorption in an endolithic layer below the dense cyanobacterial surface biofilm that could be localized to aggregates of Chroococcidiopsis-like unicellular cyanobacteria packed within a thick common sheath. High-pressure liquid chromatography-based pigment analyses showed in situ ratios of Chl f to Chl a of 5% in brown-pigmented zones of the beachrock, with lower ratios of ~0.5% in the black- and pink-pigmented biofilm zones. Enrichment experiments with black beachrock biofilm showed stimulated synthesis of Chl f and Chl d when grown under near-infrared radiation (NIR; 740 nm), with a Chl f to Chl a ratio increasing 4-fold to 2%, whereas the Chl d to Chl a ratio went from 0% to 0.8%. Enrichments grown under white light (400-700 nm) produced no detectable amounts of either Chl d or Chl f. Beachrock cyanobacteria thus exhibited characteristics of far-red light photoacclimation, enabling Chl f -containing cyanobacteria to thrive in optical niches deprived of visible light when sufficient NIR is prevalent. © 2016 Phycological Society of America.

A single phosphorus treatment doubles growth of cyanobacterial lichen transplants.

Science.gov (United States)

McCune, Bruce; Caldwell, Bruce A

2009-02-01

Lichens are reputedly slow growing and become unhealthy or die in response to supplements of the usual limiting resources, such as water and nitrogen. We found, however, that the tripartite cyanobacterial lichen Lobaria pulmonaria doubled in annual biomass growth after a single 20-minute immersion in a phosphorus solution (K2HPO4), as compared to controls receiving no supplemental phosphorus. This stimulation of cyanolichens by phosphorus has direct relevance to community and population ecology of lichens, including improving models of lichen performance in relation to air quality, improving forest management practices affecting old-growth associated cyanolichens, and understanding the distribution and abundance of cyanolichens on the landscape. Phosphorus may be as important a stimulant to cyanobacterial-rich lichen communities as it is to cyanobacteria in aquatic ecosystems.

Pax7 lineage contributions to the mammalian neural crest.

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Barbara Murdoch

Full Text Available Neural crest cells are vertebrate-specific multipotent cells that contribute to a variety of tissues including the peripheral nervous system, melanocytes, and craniofacial bones and cartilage. Abnormal development of the neural crest is associated with several human maladies including cleft/lip palate, aggressive cancers such as melanoma and neuroblastoma, and rare syndromes, like Waardenburg syndrome, a complex disorder involving hearing loss and pigment defects. We previously identified the transcription factor Pax7 as an early marker, and required component for neural crest development in chick embryos. In mammals, Pax7 is also thought to play a role in neural crest development, yet the precise contribution of Pax7 progenitors to the neural crest lineage has not been determined.Here we use Cre/loxP technology in double transgenic mice to fate map the Pax7 lineage in neural crest derivates. We find that Pax7 descendants contribute to multiple tissues including the cranial, cardiac and trunk neural crest, which in the cranial cartilage form a distinct regional pattern. The Pax7 lineage, like the Pax3 lineage, is additionally detected in some non-neural crest tissues, including a subset of the epithelial cells in specific organs.These results demonstrate a previously unappreciated widespread distribution of Pax7 descendants within and beyond the neural crest. They shed light regarding the regionally distinct phenotypes observed in Pax3 and Pax7 mutants, and provide a unique perspective into the potential roles of Pax7 during disease and development.

Temporal variation in community composition, pigmentation, and Fv/Fm of desert cyanobacterial soil crusts

Science.gov (United States)

Bowker, M.A.; Reed, S.C.; Belnap, J.; Phillips, S.L.

2002-01-01

Summers on the Colorado Plateau (USA) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high UV and visible radiation. We investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. Representative surface cores were sampled at the ENE, WSW, and top microaspects of 20 individual soil crust pedicels at a single site in Canyonlands National Park, Utah, in spring and fall of 1999. Frequency of cyanobacterial taxa, pigment concentrations, and dark adapted quantum yield (Fv/Fm) were measured for each core. The frequency of major cyanobacterial taxa was lower in the fall compared to spring. The less-pigmented cyanobacterium Microcoleus vaginatus showed significant mortality when not in the presence of Nostoc spp. and Scytonema myochrous (Dillw.) Agardh. (both synthesizers of UV radiation-linked pigments) but had little or no mortality when these species were abundant. We hypothesize that the sunscreen pigments produced by Nostoc and Scytonema in the surface of crusts protect other, less-pigmented taxa. When fall and spring samples were compared, overall cyanobacterial frequency was lower in fall, while sunscreen pigment concentrations, chlorophyll a concentration, and Fv/Fm were higher in fall. The ratio of cyanobacterial frequency/chlorophyll a concentrations was 2-3 times lower in fall than spring. Because chlorophyll a is commonly used as a surrogate measure of soil cyanobacterial biomass, these results indicate that seasonality needs to be taken into consideration. In the fall sample, most pigments associated with UV radiation protection or repair were at their highest concentrations on pedicel tops and WSW microaspects, and at their lowest concentrations on ENE microaspects. We suggest that differential pigment concentrations between microaspects are induced by varying UV radiation dosage at the soil surface on these different

Contributions of meteorology to the phenology of cyanobacterial blooms: implications for future climate change.

Science.gov (United States)

Zhang, Min; Duan, Hongtao; Shi, Xiaoli; Yu, Yang; Kong, Fanxiang

2012-02-01

Cyanobacterial blooms are often a result of eutrophication. Recently, however, their expansion has also been found to be associated with changes in climate. To elucidate the effects of climatic variables on the expansion of cyanobacterial blooms in Taihu, China, we analyzed the relationships between climatic variables and bloom events which were retrieved by satellite images. We then assessed the contribution of each climate variable to the phenology of blooms using multiple regression models. Our study demonstrates that retrieving ecological information from satellite images is meritorious for large-scale and long-term ecological research in freshwater ecosystems. Our results show that the phenological changes of blooms at an inter-annual scale are strongly linked to climate in Taihu during the past 23 yr. Cyanobacterial blooms occur earlier and last longer with the increase of temperature, sunshine hours, and global radiation and the decrease of wind speed. Furthermore, the duration increases when the daily averages of maximum, mean, and minimum temperature each exceed 20.3 °C, 16.7 °C, and 13.7 °C, respectively. Among these factors, sunshine hours and wind speed are the primary contributors to the onset of the blooms, explaining 84.6% of their variability over the past 23 yr. These factors are also good predictors of the variability in the duration of annual blooms and determined 58.9% of the variability in this parameter. Our results indicate that when nutrients are in sufficiently high quantities to sustain the formation of cyanobacterial blooms, climatic variables become crucial in predicting cyanobacterial bloom events. Climate changes should be considered when we evaluate how much the amount of nutrients should be reduced in Taihu for lake management. Copyright © 2011 Elsevier Ltd. All rights reserved.

ERK2 suppresses self-renewal capacity of embryonic stem cells, but is not required for multi-lineage commitment.

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William B Hamilton

Full Text Available Activation of the FGF-ERK pathway is necessary for naïve mouse embryonic stem (ES cells to exit self-renewal and commit to early differentiated lineages. Here we show that genetic ablation of Erk2, the predominant ERK isozyme expressed in ES cells, results in hyper-phosphorylation of ERK1, but an overall decrease in total ERK activity as judged by substrate phosphorylation and immediate-early gene (IEG induction. Normal induction of this subset of canonical ERK targets, as well as p90RSK phosphorylation, was rescued by transgenic expression of either ERK1 or ERK2 indicating a degree of functional redundancy. In contrast to previously published work, Erk2-null ES cells exhibited no detectable defect in lineage specification to any of the three germ layers when induced to differentiate in either embryoid bodies or in defined neural induction conditions. However, under self-renewing conditions Erk2-null ES cells express increased levels of the pluripotency-associated transcripts, Nanog and Tbx3, a decrease in Nanog-GFP heterogeneity, and exhibit enhanced self-renewal in colony forming assays. Transgenic add-back of ERK2 is capable of restoring normal pluripotent gene expression and self-renewal capacity. We show that ERK2 contributes to the destabilization of ES cell self-renewal by reducing expression of pluripotency genes, such as Nanog, but is not specifically required for the early stages of germ layer specification.

Chasing after Non-cyanobacterial Nitrogen Fixation in Marine Pelagic Environments

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Pia H. Moisander

2017-09-01

Full Text Available Traditionally, cyanobacterial activity in oceanic photic layers was considered responsible for the marine pelagic dinitrogen (N2 fixation. Other potentially N2-fixing bacteria and archaea have also been detected in the pelagic water column, however, the activity and importance of these non-cyanobacterial diazotrophs (NCDs remain poorly constrained. In this perspective we summarize the N2 fixation rates from recently published studies on photic and aphotic layers that have been attributed to NCD activity via parallel molecular measurements, and discuss the status, challenges, and data gaps in estimating non-cyanobacterial N2 fixation NCNF in the ocean. Rates attributed to NCNF have generally been near the detection limit thus far (<1 nmol N L−1 d−1. Yet, if considering the large volume of the dark ocean, even low rates of NCNF could make a significant contribution to the new nitrogen input to the ocean. The synthesis here shows that nifH transcription data for NCDs have been reported in only a few studies where N2 fixation rates were detected in the absence of diazotrophic cyanobacteria. In addition, high apparent diversity and regional variability in the NCDs complicate investigations of these communities. Future studies should focus on further investigating impacts of environmental drivers including oxygen, dissolved organic matter, and dissolved inorganic nitrogen on NCNF. Describing the ecology of NCDs and accurately measuring NCNF rates, are critical for a future evaluation of the contribution of NCNF to the marine nitrogen budget.

T-cell clones from Th1, Th17 or Th1/17 lineages and their signature cytokines have different capacity to activate endothelial cells or synoviocytes.

Science.gov (United States)

Lavocat, Fabien; Maggi, Laura; Annunziato, Francesco; Miossec, Pierre

2016-12-01

To compare the direct effect of cytokines on synoviocytes and endothelial cells to the effects of supernatants from Th1, Th17 and Th1/17 clones and the direct cell-cell interactions with the same clones. Th17 and Th1/17 clones were obtained from the CD161+CCR6+ fraction and Th1 clones from the CD161-CCR6- fraction of human CD4+ T-cells. Endothelial cells or synoviocytes were cultured in the presence of either isolated pro-inflammatory cytokines (IL-17 and/or TNF-α) or supernatants from the T-cell clones or co-cultured with T-cell clones themselves. IL-6 and IL-8 expression and production were analyzed. IL-17 and TNF-α induced IL-6 and IL-8 expression, although IL-17 alone had a limited effect on endothelial cells compared to synoviocytes. Supernatants from activated T-helper clones also induced IL-6 and IL-8 expression but with discrepancies between endothelial cells and synoviocytes. Endothelial cells were mostly activated by Th1 clone supernatants whereas synoviocytes were activated by all T-cell subtypes. Finally, cell-cell contact experiments showed a great heterogeneity among cell clones, even from the same lineage. IL-6 expression was mostly induced by contact with Th1 clones both in endothelial and mesenchymal cells whereas IL-8 expression was induced by all T-cell clones whatever their phenotype. We showed that endothelial cells were much more sensitive to Th1 activation whereas synoviocytes were activated by all T-helper lineages. This work highlights the heterogeneity of interactions between T-cells and stromal cells through soluble factors or direct cell contact. Copyright © 2016 Elsevier Ltd. All rights reserved.

Even Cancers Want Commitment: Lineage Identity and Medulloblastoma Formation

Science.gov (United States)

Eberhart, Charles G.

2015-01-01

In this issue of Cancer Cell, Yang et al. (2008) and Schüller et al. (2008) show that Hedgehog activation in either multipotent neural stem cells or developmentally restricted progenitors causes only medulloblastomas to form. These data suggest that some stem cell-derived tumors must commit to a specific lineage in order to grow. PMID:18691544

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming

2014-04-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge\\'s mild intercellular environment. 2014 Gao et al.

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Bajic, Vladimir B.; Qian, Pei-Yuan

2014-01-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. 2014 Gao et al.

Limnology and cyanobacterial diversity of high altitude lakes of ...

Indian Academy of Sciences (India)

Limnological data of four high altitude lakes from the cold desert region of Himachal Pradesh, India, has been correlated with cyanobacterial diversity. Physico-chemical characteristics and nutrient contents of the studied lakes revealed that Sissu Lake is mesotrophic while Chandra Tal, Suraj Tal and Deepak Tal are ...

ROCK inhibitor primes human induced pluripotent stem cells to selectively differentiate towards mesendodermal lineage via epithelial-mesenchymal transition-like modulation

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Maricela Maldonado

2016-09-01

Full Text Available Robust control of human induced pluripotent stem cell (hIPSC differentiation is essential to realize its patient-tailored therapeutic potential. Here, we demonstrate a novel application of Y-27632, a small molecule Rho-associated protein kinase (ROCK inhibitor, to significantly influence the differentiation of hIPSCs in a lineage-specific manner. The application of Y-27632 to hIPSCs resulted in a decrease in actin bundling and disruption of colony formation in a concentration and time-dependent manner. Such changes in cell and colony morphology were associated with decreased expression of E-cadherin, a cell-cell junctional protein, proportional to the increased exposure to Y-27632. Interestingly, gene and protein expression of pluripotency markers such as NANOG and OCT4 were not downregulated by an exposure to Y-27632 up to 36 h. Simultaneously, epithelial-to-mesenchymal (EMT transition markers were upregulated with an exposure to Y-27632. These EMT-like changes in the cells with longer exposure to Y-27632 resulted in a significant increase in the subsequent differentiation efficiency towards mesendodermal lineage. In contrast, an inhibitory effect was observed when cells were subjected to ectodermal differentiation after prolonged exposure to Y-27632. Collectively, these results present a novel method for priming hIPSCs to modulate their differentiation potential with a simple application of Y-27632.

Rat bone marrow progenitor cells transduced in situ by rSV40 vectors differentiate into multiple central nervous system cell lineages.

Science.gov (United States)

Louboutin, Jean-Pierre; Liu, Bianling; Reyes, Beverly A S; Van Bockstaele, Elisabeth J; Strayer, David S

2006-12-01

Using bone marrow-directed gene transfer, we tested whether bone marrow-derived cells may function as progenitors of central nervous system (CNS) cells in adult animals. SV40-derived gene delivery vectors were injected directly into femoral bone marrow, and we examined transgene expression in blood and brain for 0-16 months thereafter by immunostaining for FLAG epitope marker. An average of 5% of peripheral blood cells and 25% of femoral marrow cells were FLAG(+) throughout the study. CNS FLAG-expressing cells were mainly detected in the dentate gyrus (DG) and periventricular subependymal zone (PSZ). Although absent before 1 month and rare at 4 months, DG and PSZ FLAG(+) cells were abundant 16 months after bone marrow injection. Approximately 5% of DG cells expressed FLAG, including neurons (48.6%) and microglia (49.7%), and occasional astrocytes (1.6%), as determined by double immunostaining for FLAG and lineage markers. These data suggest that one or more populations of cells resident within adult bone marrow can migrate to the brain and differentiate into CNS-specific cells.

Endometrial Cancer Side-Population Cells Show Prominent Migration and Have a Potential to Differentiate into the Mesenchymal Cell Lineage

Science.gov (United States)

Kato, Kiyoko; Takao, Tomoka; Kuboyama, Ayumi; Tanaka, Yoshihiro; Ohgami, Tatsuhiro; Yamaguchi, Shinichiro; Adachi, Sawako; Yoneda, Tomoko; Ueoka, Yousuke; Kato, Keiji; Hayashi, Shinichi; Asanoma, Kazuo; Wake, Norio

2010-01-01

Cancer stem-like cell subpopulations, referred to as “side-population” (SP) cells, have been identified in several tumors based on their ability to efflux the fluorescent dye Hoechst 33342. Although SP cells have been identified in the normal human endometrium and endometrial cancer, little is known about their characteristics. In this study, we isolated and characterized the SP cells in human endometrial cancer cells and in rat endometrial cells expressing oncogenic human K-Ras protein. These SP cells showed i) reduction in the expression levels of differentiation markers; ii) long-term proliferative capacity of the cell cultures; iii) self-renewal capacity in vitro; iv) enhancement of migration, lamellipodia, and, uropodia formation; and v) enhanced tumorigenicity. In nude mice, SP cells formed large, invasive tumors, which were composed of both tumor cells and stromal-like cells with enriched extracellular matrix. The expression levels of vimentin, α-smooth muscle actin, and collagen III were enhanced in SP tumors compared with the levels in non-SP tumors. In addition, analysis of microdissected samples and fluorescence in situ hybridization of Hec1-SP-tumors showed that the stromal-like cells with enriched extracellular matrix contained human DNA, confirming that the stromal-like cells were derived from the inoculated cells. Moreober, in a Matrigel assay, SP cells differentiated into α-smooth muscle actin-expressing cells. These findings demonstrate that SP cells have cancer stem-like cell features, including the potential to differentiate into the mesenchymal cell lineage. PMID:20008133

Trophic factors from adipose tissue-derived multi-lineage progenitor cells promote cytodifferentiation of periodontal ligament cells

International Nuclear Information System (INIS)

Sawada, Keigo; Takedachi, Masahide; Yamamoto, Satomi; Morimoto, Chiaki; Ozasa, Masao; Iwayama, Tomoaki; Lee, Chun Man; Okura, Hanayuki; Matsuyama, Akifumi; Kitamura, Masahiro; Murakami, Shinya

2015-01-01

Stem and progenitor cells are currently being investigated for their applicability in cell-based therapy for periodontal tissue regeneration. We recently demonstrated that the transplantation of adipose tissue-derived multi-lineage progenitor cells (ADMPCs) enhances periodontal tissue regeneration in beagle dogs. However, the molecular mechanisms by which transplanted ADMPCs induce periodontal tissue regeneration remain to be elucidated. In this study, trophic factors released by ADMPCs were examined for their paracrine effects on human periodontal ligament cell (HPDL) function. ADMPC conditioned medium (ADMPC-CM) up-regulated osteoblastic gene expression, alkaline phosphatase activity and calcified nodule formation in HPDLs, but did not significantly affect their proliferative response. ADMPCs secreted a number of growth factors, including insulin-like growth factor binding protein 6 (IGFBP6), hepatocyte growth factor and vascular endothelial growth factor. Among these, IGFBP6 was most highly expressed. Interestingly, the positive effects of ADMPC-CM on HPDL differentiation were significantly suppressed by transfecting ADMPCs with IGFBP6 siRNA. Our results suggest that ADMPCs transplanted into a defect in periodontal tissue release trophic factors that can stimulate the differentiation of HPDLs to mineralized tissue-forming cells, such as osteoblasts and cementoblasts. IGFBP6 may play crucial roles in ADMPC-induced periodontal regeneration. - Highlights: • ADMPC-derived humoral factors stimulate cytodifferentiation of HPDLs. • ADMPCs secret growth factors including IGFBP6, VEGF and HGF. • IGFBP6 is involved in the promotion effect of ADMPC-CM on HPDL cytodifferentiation

Trophic factors from adipose tissue-derived multi-lineage progenitor cells promote cytodifferentiation of periodontal ligament cells

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Sawada, Keigo [Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka (Japan); Takedachi, Masahide, E-mail: takedati@dent.osaka-u.ac.jp [Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka (Japan); Yamamoto, Satomi; Morimoto, Chiaki; Ozasa, Masao; Iwayama, Tomoaki [Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka (Japan); Lee, Chun Man [Medical Center for Translational Research, Osaka University Hospital, Osaka (Japan); Okura, Hanayuki; Matsuyama, Akifumi [Research on Disease Bioresources, Platform of Therapeutics for Rare Disease, National Institute of Biomedical Innovation, Osaka (Japan); Kitamura, Masahiro; Murakami, Shinya [Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka (Japan)

2015-08-14

Stem and progenitor cells are currently being investigated for their applicability in cell-based therapy for periodontal tissue regeneration. We recently demonstrated that the transplantation of adipose tissue-derived multi-lineage progenitor cells (ADMPCs) enhances periodontal tissue regeneration in beagle dogs. However, the molecular mechanisms by which transplanted ADMPCs induce periodontal tissue regeneration remain to be elucidated. In this study, trophic factors released by ADMPCs were examined for their paracrine effects on human periodontal ligament cell (HPDL) function. ADMPC conditioned medium (ADMPC-CM) up-regulated osteoblastic gene expression, alkaline phosphatase activity and calcified nodule formation in HPDLs, but did not significantly affect their proliferative response. ADMPCs secreted a number of growth factors, including insulin-like growth factor binding protein 6 (IGFBP6), hepatocyte growth factor and vascular endothelial growth factor. Among these, IGFBP6 was most highly expressed. Interestingly, the positive effects of ADMPC-CM on HPDL differentiation were significantly suppressed by transfecting ADMPCs with IGFBP6 siRNA. Our results suggest that ADMPCs transplanted into a defect in periodontal tissue release trophic factors that can stimulate the differentiation of HPDLs to mineralized tissue-forming cells, such as osteoblasts and cementoblasts. IGFBP6 may play crucial roles in ADMPC-induced periodontal regeneration. - Highlights: • ADMPC-derived humoral factors stimulate cytodifferentiation of HPDLs. • ADMPCs secret growth factors including IGFBP6, VEGF and HGF. • IGFBP6 is involved in the promotion effect of ADMPC-CM on HPDL cytodifferentiation.

Visualization and correction of automated segmentation, tracking and lineaging from 5-D stem cell image sequences.

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Wait, Eric; Winter, Mark; Bjornsson, Chris; Kokovay, Erzsebet; Wang, Yue; Goderie, Susan; Temple, Sally; Cohen, Andrew R

2014-10-03

Neural stem cells are motile and proliferative cells that undergo mitosis, dividing to produce daughter cells and ultimately generating differentiated neurons and glia. Understanding the mechanisms controlling neural stem cell proliferation and differentiation will play a key role in the emerging fields of regenerative medicine and cancer therapeutics. Stem cell studies in vitro from 2-D image data are well established. Visualizing and analyzing large three dimensional images of intact tissue is a challenging task. It becomes more difficult as the dimensionality of the image data increases to include time and additional fluorescence channels. There is a pressing need for 5-D image analysis and visualization tools to study cellular dynamics in the intact niche and to quantify the role that environmental factors play in determining cell fate. We present an application that integrates visualization and quantitative analysis of 5-D (x,y,z,t,channel) and large montage confocal fluorescence microscopy images. The image sequences show stem cells together with blood vessels, enabling quantification of the dynamic behaviors of stem cells in relation to their vascular niche, with applications in developmental and cancer biology. Our application automatically segments, tracks, and lineages the image sequence data and then allows the user to view and edit the results of automated algorithms in a stereoscopic 3-D window while simultaneously viewing the stem cell lineage tree in a 2-D window. Using the GPU to store and render the image sequence data enables a hybrid computational approach. An inference-based approach utilizing user-provided edits to automatically correct related mistakes executes interactively on the system CPU while the GPU handles 3-D visualization tasks. By exploiting commodity computer gaming hardware, we have developed an application that can be run in the laboratory to facilitate rapid iteration through biological experiments. We combine unsupervised image

On the use of high-throughput sequencing for the study of cyanobacterial diversity in Antarctic aquatic mats.

Science.gov (United States)

Pessi, Igor Stelmach; Maalouf, Pedro De Carvalho; Laughinghouse, Haywood Dail; Baurain, Denis; Wilmotte, Annick

2016-06-01

The study of Antarctic cyanobacterial diversity has been mostly limited to morphological identification and traditional molecular techniques. High-throughput sequencing (HTS) allows a much better understanding of microbial distribution in the environment, but its application is hampered by several methodological and analytical challenges. In this work, we explored the use of HTS as a tool for the study of cyanobacterial diversity in Antarctic aquatic mats. Our results highlight the importance of using artificial communities to validate the parameters of the bioinformatics procedure used to analyze natural communities, since pipeline-dependent biases had a strong effect on the observed community structures. Analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic showed that HTS is a valuable tool for the assessment of cyanobacterial diversity. The majority of the operational taxonomic units retrieved were related to filamentous taxa such as Leptolyngbya and Phormidium, which are common genera in Antarctic lacustrine microbial mats. However, other phylotypes related to different taxa such as Geitlerinema, Pseudanabaena, Synechococcus, Chamaesiphon, Calothrix, and Coleodesmium were also found. Results revealed a much higher diversity than what had been reported using traditional methods and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. The aquatic biofilm from the Sub-Antarctic had a distinct cyanobacterial community from the Antarctic lakes, which in turn displayed a salinity-dependent community structure at the phylotype level. © 2016 Phycological Society of America.

Defining the Minimal Factors Required for Erythropoiesis through Direct Lineage Conversion

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Sandra Capellera-Garcia

2016-06-01

Full Text Available Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of well characterized genes. However, the minimal set of factors necessary for instructing red blood cell (RBC development remains undefined. We employed a screen for transcription factors allowing direct lineage reprograming from fibroblasts to induced erythroid progenitors/precursors (iEPs. We show that Gata1, Tal1, Lmo2, and c-Myc (GTLM can rapidly convert murine and human fibroblasts directly to iEPs. The transcriptional signature of murine iEPs resembled mainly that of primitive erythroid progenitors in the yolk sac, whereas addition of Klf1 or Myb to the GTLM cocktail resulted in iEPs with a more adult-type globin expression pattern. Our results demonstrate that direct lineage conversion is a suitable platform for defining and studying the core factors inducing the different waves of erythroid development.

Evidence of two distinct functionally specialized fibroblast lineages in breast stroma

DEFF Research Database (Denmark)

Morsing, Mikkel; Klitgaard, Marie Christine; Jafari Kermani, Abbas

2016-01-01

Background The terminal duct lobular unit (TDLU) is the most dynamic structure in the human breast and the putative site of origin of human breast cancer. Although stromal cells contribute to a specialized microenvironment in many organs, this component remains largely understudied in the human...... conditions followed by analysis of adipogenic and osteogenic differentiation. To test whether the two fibroblast lineages are functionally imprinted by their site of origin, single cell sorted CD271low/MUC1high normal breast luminal epithelial cells are plated on fibroblast feeders for the observation...... fibroblast lineages exist in the normal human breast, of which the lobular fibroblasts have properties in common with mesenchymal stem cells and support epithelial growth and morphogenesis. We propose that lobular fibroblasts constitute a specialized microenvironment for human breast luminal epithelial...

In vitro analysis of the oligodendrocyte lineage in mice during demyelination and remyelination

International Nuclear Information System (INIS)

Armstrong, R.; Friedrich, V.L. Jr.; Holmes, K.V.; Dubois-Dalcq, M.

1990-01-01

A demyelinating disease induced in C57B1/6N mice by intracranial injection of a coronavirus (murine hepatitis virus strain A59) is followed by functional recovery and efficient CNS myelin repair. To study the biological properties of the cells involved in this repair process, glial cells were isolated and cultured from spinal cords of these young adult mice during demyelination and remyelination. Using three-color immunofluorescence combined with [3H]thymidine autoradiography, we have analyzed the antigenic phenotype and mitotic potential of individual glial cells. We identified oligodendrocytes with an antibody to galactocerebroside, astrocytes with an antibody to glial fibrillary acidic protein, and oligodendrocyte-type 2 astrocyte (O-2A) progenitor cells with the O4 antibody. Cultures from demyelinated tissue differed in several ways from those of age-matched controls: first, the total number of O-2A lineage cells was strikingly increased; second, the O-2A population consisted of a higher proportion of O4-positive astrocytes and cells of mixed oligodendrocyte-astrocyte phenotype; and third, all the cell types within the O-2A lineage showed enhanced proliferation. This proliferation was not further enhanced by adding PDGF, basic fibroblast growth factor (bFGF), or insulin-like growth factor I (IGF-I) to the defined medium. However, bFGF and IGF-I seemed to influence the fate of O-2A lineage cells in cultures of demyelinated tissue. Basic FGF decreased the percentage of cells expressing galactocerebroside. In contrast, IGF-I increased the relative proportion of oligodendrocytes. Thus, O-2A lineage cells from adult mice display greater phenotypic plasticity and enhanced mitotic potential in response to an episode of demyelination. These properties may be linked to the efficient remyelination achieved in this demyelinating disease

Book review: Handbook of cyanobacterial monitoring and cyanotoxin analysis

Science.gov (United States)

Graham, Jennifer L.; Loftin, Keith A.

2018-01-01

Review of Meriluoto, Jussi, Lisa Spoof, and GeoffreyA. Codd [eds.]. 2017. Handbook of Cyanobacterial Monitoring and Cyanotoxin Analysis. John Wiley & Sons, Ltd.: Chichester, West Sussex, UK, ISBN 978‐1‐119‐06868‐6 (978‐1‐119‐06876‐1 eBook), DOI 10.1002/9781119068761.

Insights from Cyanobacterial Genomes for the Development of Extraterrestrial Photoautotrophic Biotechnologies

Science.gov (United States)

Brown, I. I.; Bryant, D. A.; Tringe, S. G.; Malley, K.; Sosa, O.; Sarkisova, S. A.; Garrison, D. H.; McKay, D. S.

2010-04-01

Using genomic and metagenomic analysis, Fe-tolerant cyanobacterial species with a large and diverse set of stress-tolerant genes, were identified as prime candidates for in situ resource utilization in a biogeoreactor at extraterrestrial outposts.

MODIS observations of cyanobacterial risks in a eutrophic lake: Implications for long-term safety evaluation in drinking-water source.

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Duan, Hongtao; Tao, Min; Loiselle, Steven Arthur; Zhao, Wei; Cao, Zhigang; Ma, Ronghua; Tang, Xiaoxian

2017-10-01

The occurrence and related risks from cyanobacterial blooms have increased world-wide over the past 40 years. Information on the abundance and distribution of cyanobacteria is fundamental to support risk assessment and management activities. In the present study, an approach based on Empirical Orthogonal Function (EOF) analysis was used to estimate the concentrations of chlorophyll a (Chla) and the cyanobacterial biomarker pigment phycocyanin (PC) using data from the MODerate resolution Imaging Spectroradiometer (MODIS) in Lake Chaohu (China's fifth largest freshwater lake). The approach was developed and tested using fourteen years (2000-2014) of MODIS images, which showed significant spatial and temporal variability of the PC:Chla ratio, an indicator of cyanobacterial dominance. The results had unbiased RMS uncertainties of MODIS Chla and PC products were then used for cyanobacterial risk mapping with a decision tree classification model. The resulting Water Quality Decision Matrix (WQDM) was designed to assist authorities in the identification of possible intake areas, as well as specific months when higher frequency monitoring and more intense water treatment would be required if the location of the present intake area remained the same. Remote sensing cyanobacterial risk mapping provides a new tool for reservoir and lake management programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Robust Differentiation of mRNA-Reprogrammed Human Induced Pluripotent Stem Cells Toward a Retinal Lineage.

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Sridhar, Akshayalakshmi; Ohlemacher, Sarah K; Langer, Kirstin B; Meyer, Jason S

2016-04-01

The derivation of human induced pluripotent stem cells (hiPSCs) from patient-specific sources has allowed for the development of novel approaches to studies of human development and disease. However, traditional methods of generating hiPSCs involve the risks of genomic integration and potential constitutive expression of pluripotency factors and often exhibit low reprogramming efficiencies. The recent description of cellular reprogramming using synthetic mRNA molecules might eliminate these shortcomings; however, the ability of mRNA-reprogrammed hiPSCs to effectively give rise to retinal cell lineages has yet to be demonstrated. Thus, efforts were undertaken to test the ability and efficiency of mRNA-reprogrammed hiPSCs to yield retinal cell types in a directed, stepwise manner. hiPSCs were generated from human fibroblasts via mRNA reprogramming, with parallel cultures of isogenic human fibroblasts reprogrammed via retroviral delivery of reprogramming factors. New lines of mRNA-reprogrammed hiPSCs were established and were subsequently differentiated into a retinal fate using established protocols in a directed, stepwise fashion. The efficiency of retinal differentiation from these lines was compared with retroviral-derived cell lines at various stages of development. On differentiation, mRNA-reprogrammed hiPSCs were capable of robust differentiation to a retinal fate, including the derivation of photoreceptors and retinal ganglion cells, at efficiencies often equal to or greater than their retroviral-derived hiPSC counterparts. Thus, given that hiPSCs derived through mRNA-based reprogramming strategies offer numerous advantages owing to the lack of genomic integration or constitutive expression of pluripotency genes, such methods likely represent a promising new approach for retinal stem cell research, in particular, those for translational applications. In the current report, the ability to derive mRNA-reprogrammed human induced pluripotent stem cells (hi

Two Marine Cyanobacterial Aplysiatoxin Polyketides, Neo-debromoaplysiatoxin A and B, with K+ Channel Inhibition Activity.

Science.gov (United States)

Han, Bing-Nan; Liang, Ting-Ting; Keen, Lawrence Jordan; Fan, Ting-Ting; Zhang, Xiao-Dan; Xu, Lin; Zhao, Qi; Wang, Shu-Ping; Lin, Hou-Wen

2018-02-02

The isolation and structure elucidation of two cyanobacterial debromoaplysiatoxin (DAT) analogues, neo-debromoaplysiatoxin A (1) and neo-debromoaplysiatoxin B (2), were reported and found to possess 6/10/6 and 6/6/6 fused-ring systems, respectively, which are rarely seen among aplysiatoxins. Both compounds exhibited potent blocking activity against Kv1.5 with IC 50 values of 6.94 ± 0.26 and 0.30 ± 0.05 μM, respectively. These findings suggest the potential of aplysiatoxin analogues in modulating ionic channels and also provide links between the DAT target, protein kinase C, and cell regulation.

Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms.

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Mélanie Gerphagnon

Full Text Available Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids. However, few studies have reported the effects of fungal parasites on filamentous cyanobacterial blooms. To investigate the missing components of bloom ecosystems, we examined an entire field bloom of the cyanobacterium Anabaena macrospora for evidence of chytrid infection in a productive freshwater lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus Rhizosiphon which have similar life cycles but differed in their infective regimes depending on the cellular niches offered by their host. R. crassum infected both vegetative cells and akinetes while R. akinetum infected only akinetes. A tentative reconstruction of the developmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection affected 6% of total cells (and 4% of akinètes, spread over a maximum of 17% of the filaments of cyanobacteria, in which 60% of the cells could be parasitized. Furthermore, chytrids may reduce the length of filaments of Anabaena macrospora significantly by "mechanistic fragmentation" following infection. All these results suggest that chytrid parasitism is one of the driving factors involved in the decline of a cyanobacteria blooms, by direct mortality of parasitized cells and indirectly by the mechanistic fragmentation, which could weaken the resistance of A. macrospora to grazing.

Response of cyanobacterial mats to nutrient and salinity changes

Czech Academy of Sciences Publication Activity Database

Rejmánková, E.; Komárková, Jaroslava

2005-01-01

Roč. 83, č. 2 (2005), s. 87-107 ISSN 0304-3770. [INTECOL International Wetlands Conference /7./. Utrecht, 25.07.2004-30.7.2004] Grant - others:NSF(US) 0089211 Institutional research plan: CEZ:AV0Z60170517 Keywords : cyanobacterial mats * Belize * P-N impact Subject RIV: EH - Ecology, Behaviour Impact factor: 1.344, year: 2005

ROCK inhibitor primes human induced pluripotent stem cells to selectively differentiate towards mesendodermal lineage via epithelial-mesenchymal transition-like modulation.

Science.gov (United States)

Maldonado, Maricela; Luu, Rebeccah J; Ramos, Michael E P; Nam, Jin

2016-09-01

Robust control of human induced pluripotent stem cell (hIPSC) differentiation is essential to realize its patient-tailored therapeutic potential. Here, we demonstrate a novel application of Y-27632, a small molecule Rho-associated protein kinase (ROCK) inhibitor, to significantly influence the differentiation of hIPSCs in a lineage-specific manner. The application of Y-27632 to hIPSCs resulted in a decrease in actin bundling and disruption of colony formation in a concentration and time-dependent manner. Such changes in cell and colony morphology were associated with decreased expression of E-cadherin, a cell-cell junctional protein, proportional to the increased exposure to Y-27632. Interestingly, gene and protein expression of pluripotency markers such as NANOG and OCT4 were not downregulated by an exposure to Y-27632 up to 36h. Simultaneously, epithelial-to-mesenchymal (EMT) transition markers were upregulated with an exposure to Y-27632. These EMT-like changes in the cells with longer exposure to Y-27632 resulted in a significant increase in the subsequent differentiation efficiency towards mesendodermal lineage. In contrast, an inhibitory effect was observed when cells were subjected to ectodermal differentiation after prolonged exposure to Y-27632. Collectively, these results present a novel method for priming hIPSCs to modulate their differentiation potential with a simple application of Y-27632. Copyright © 2016 Helmholtz Zentrum München. Published by Elsevier B.V. All rights reserved.

Linking cascading effects of fish predation and zooplankton grazing to reduced cyanobacterial biomass and toxin levels following biomanipulation.

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Mattias K Ekvall

Full Text Available Eutrophication has been one of the largest environmental problems in aquatic ecosystems during the past decades, leading to dense, and often toxic, cyanobacterial blooms. In a way to counteract these problems many lakes have been subject to restoration through biomanipulation. Here we combine 13 years of monitoring data with experimental assessment of grazing efficiency of a naturally occurring zooplankton community and a, from a human perspective, desired community of large Daphnia to assess the effects of an altered trophic cascade associated with biomanipulation. Lake monitoring data show that the relative proportion of Daphnia spp. grazers in June has increased following years of biomanipulation and that this increase coincides with a drop in cyanobacterial biomass and lowered microcystin concentrations compared to before the biomanipulation. In June, the proportion of Daphnia spp. (on a biomass basis went from around 3% in 2005 (the first year of biomanipulation up to around 58% in 2012. During months when the proportion of Daphnia spp. remained unchanged (July and August no effect on lower trophic levels was observed. Our field grazing experiment revealed that Daphnia were more efficient in controlling the standing biomass of cyanobacteria, as grazing by the natural zooplankton community never even compensated for the algal growth during the experiment and sometimes even promoted cyanobacterial growth. Furthermore, although the total cyanobacterial toxin levels remained unaffected by both grazer communities in the experimental study, the Daphnia dominated community promoted the transfer of toxins to the extracellular, dissolved phase, likely through feeding on cyanobacteria. Our results show that biomanipulation by fish removal is a useful tool for lake management, leading to a top-down mediated trophic cascade, through alterations in the grazer community, to reduced cyanobacterial biomass and lowered cyanobacterial toxin levels. This

Polo-Like Kinase 2 is Dynamically Regulated to Coordinate Proliferation and Early Lineage Specification Downstream of Yes-Associated Protein 1 in Cardiac Progenitor Cells.

Science.gov (United States)

Mochizuki, Michika; Lorenz, Vera; Ivanek, Robert; Della Verde, Giacomo; Gaudiello, Emanuele; Marsano, Anna; Pfister, Otmar; Kuster, Gabriela M

2017-10-24

Recent studies suggest that adult cardiac progenitor cells (CPCs) can produce new cardiac cells. Such cell formation requires an intricate coordination of progenitor cell proliferation and commitment, but the molecular cues responsible for this regulation in CPCs are ill defined. Extracellular matrix components are important instructors of cell fate. Using laminin and fibronectin, we induced two slightly distinct CPC phenotypes differing in proliferation rate and commitment status and analyzed the early transcriptomic response to CPC adhesion (<2 hours). Ninety-four genes were differentially regulated on laminin versus fibronectin, consisting of mostly downregulated genes that were enriched for Yes-associated protein (YAP) conserved signature and TEA domain family member 1 (TEAD1)-related genes. This early gene regulation was preceded by the rapid cytosolic sequestration and degradation of YAP on laminin. Among the most strongly regulated genes was polo-like kinase 2 ( Plk2 ). Plk2 expression depended on YAP stability and was enhanced in CPCs transfected with a nuclear-targeted mutant YAP. Phenotypically, the early downregulation of Plk2 on laminin was succeeded by lower cell proliferation, enhanced lineage gene expression (24 hours), and facilitated differentiation (3 weeks) compared with fibronectin. Finally, overexpression of Plk2 enhanced CPC proliferation and knockdown of Plk2 induced the expression of lineage genes. Plk2 acts as coordinator of cell proliferation and early lineage commitment in CPCs. The rapid downregulation of Plk2 on YAP inactivation marks a switch towards enhanced commitment and facilitated differentiation. These findings link early gene regulation to cell fate and provide novel insights into how CPC proliferation and differentiation are orchestrated. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Accumulation of cyanobacterial toxins in freshwater 'seafood' and its consequences for public health: A review

International Nuclear Information System (INIS)

Ibelings, Bas W.; Chorus, Ingrid

2007-01-01

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in 'seafood' collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and the likelihood of bioaccumulation discussed; (b) we derive cyanotoxin doses likely to occur through seafood consumption and propose guideline values for seafood and compare these to guidelines for drinking water; and (c) we discuss means to assess, control or mitigate the risks of exposure to cyanotoxins through seafood consumption. This is discussed in the context of two specific procedures, the food specific HACCP-approach and the water-specific Water Safety Plan approach by the WHO. Risks of exposure to cyanotoxins in food are sometimes underestimated. Risk assessments should acknowledge this and investigate the partitioning of exposure between drinking-water and food, which may vary depending on local circumstances. - Accumulation of cyanobacterial toxins in freshwater 'seafood'

Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages.

Science.gov (United States)

Jacob, Alison S; Busby, Eloise J; Levy, Abigail D; Komm, Natasha; Clark, C Graham

2016-01-01

Removing the requirement for cell culture has led to a substantial increase in the number of lineages of Entamoeba recognized as distinct. Surveying the range of potential host species for this parasite genus has barely been started and it is clear that additional sampling of the same host in different locations often identifies additional diversity. In this study, using small subunit ribosomal RNA gene sequencing, we identify four new lineages of Entamoeba, including the first report of Entamoeba from an elephant, and extend the host range of some previously described lineages. In addition, examination of microbiome data from a number of host animals suggests that substantial Entamoeba diversity remains to be uncovered. © 2015 The Author(s) Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.

To prevent the occurrence of black water agglomerate through delaying decomposition of cyanobacterial bloom biomass by sediment microbial fuel cell.

Science.gov (United States)

Zhou, Yan-Li; Jiang, He-Long; Cai, Hai-Yuan

2015-04-28

Settlement of cyanobacterial bloom biomass (CBB) into sediments in eutrophic lakes often induced the occurrence of black water agglomerate and then water quality deterioration. This study investigated the effect of sediment microbial fuel cell (SMFC) on CBB removal in sediments and related water pollution. Sediment bulking and subsequent black water from decomposition of settled CBB happened without SMFC, but were not observed over 100-day experiments with SMFC employment. While CBB in sediments improved power production from SMFC, the removal efficiency of organic matters in CBB-amended sediments with SMFC was significantly lower than that without SMFC. Pyrosequencing analysis showed higher abundances of the fermentative Clostridium and acetoclastic methanogen in CBB-amended bulk sediments without SMFC than with SMFC at the end of experiments. Obviously, SMFC operation changed the microbial community in CBB-amended sediments, and delayed the CBB degradation against sediment bulking. Thus, SMFC could be potentially applied as pollution prevention in CBB-settled and sensitive zones in shallow lakes. Copyright © 2015 Elsevier B.V. All rights reserved.

Advances in cyanobacterial polyhydroxyalkanoates production.

Science.gov (United States)

Singh, Akhilesh Kumar; Mallick, Nirupama

2017-11-01

Polyhydroxyalkanoates (PHAs) have received much attention in the current scenario due to their attractive material properties, namely biodegradability, biocompatibility, thermoplasticity, hydrophobicity, piezoelectricity and stereospecificity. All these properties make them highly competitive for various industrial applications similar to non-degradable conventional plastics. In PHA biosynthesis, PHA synthase acts as a natural catalyst for PHA polymerization process using the (R)-hydroxyacyl-CoA as substrate. Cyanobacteria can accumulate PHAs under photoautotrophic and/or mixotrophic growth conditions with organic substrates such as acetate, glucose, propionate, valerate, and so on. The natural incidence of PHA accumulation by the cyanobacteria is known since 1966. Nevertheless, PHA accumulation in cyanobacteria based on the cell biomass and volumetric productivity is critically lower than the heterotrophic bacteria. Consequently, cyanobacteria are nowadays not considered for commercial production of PHAs. Thus, strain improvements by genetic modification, new cultivation and harvesting techniques, advanced photobioreactor development, efficient and sustainable downstream processes, alternate economical carbon sources and usage of various metabolic inhibitors are suggested for enhancing cyanobacterial PHA accumulation. In addition, identification of transcriptional regulators like RNA polymerase sigma factor (SigE) and a response regulator (Rre37) together with the recent major scientific breakthrough on the existence of complete Krebs cycle in cyanobacteria would be helpful in taking PHA production from cyanobacteria to a new-fangled height in near future. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Exome Sequencing of Bilateral Testicular Germ Cell Tumors Suggests Independent Development Lineages

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Sigmund Brabrand

2015-02-01

Full Text Available Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs, is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors, of these three patients in whom both tumors were available (six tumors and two patients each with only one available tumor (two tumors. Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21, some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA, and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients.

Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes

Czech Academy of Sciences Publication Activity Database

Tóth, T. N.; Chukhutsina, V.; Knoppová, Jana; Komenda, Josef; Kis, M.; Lenart, Z.; Garab, G.; Kovács, L.; Gombos, Z.; van Amerongen, H.

2015-01-01

Roč. 1847, č. 10 (2015), s. 1153-1165 ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055; GA MŠk LO1416 Institutional support: RVO:61388971 Keywords : Carotenoid deficiency * Cyanobacterial photosynthesis * Phycobilisome Subject RIV: CE - Biochemistry Impact factor: 4.864, year: 2015

Notch lineages and activity in intestinal stem cells determined by a new set of knock-in mice.

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Silvia Fre

Full Text Available The conserved role of Notch signaling in controlling intestinal cell fate specification and homeostasis has been extensively studied. Nevertheless, the precise identity of the cells in which Notch signaling is active and the role of different Notch receptor paralogues in the intestine remain ambiguous, due to the lack of reliable tools to investigate Notch expression and function in vivo. We generated a new series of transgenic mice that allowed us, by lineage analysis, to formally prove that Notch1 and Notch2 are specifically expressed in crypt stem cells. In addition, a novel Notch reporter mouse, Hes1-EmGFP(SAT, demonstrated exclusive Notch activity in crypt stem cells and absorptive progenitors. This roster of knock-in and reporter mice represents a valuable resource to functionally explore the Notch pathway in vivo in virtually all tissues.

Chicken globin gene transcription is cell lineage specific during the time of the switch

International Nuclear Information System (INIS)

Lois, R.; Martinson, H.G.

1989-01-01

Posttranscriptional silencing of embryonic globin gene expression occurs during hemoglobin switching in chickens. Here the authors use Percoll density gradients to fractionate the red blood cells of 5-9 day embryos in order to determine the cellular source and the timing of this posttranscriptional process. By means of nuclear run-on transcription in vitro they show that it is within mature primitive cells that production of embryonic globin mRNA is terminated posttranscriptionally. In contrast, young definitive cells produce little (or no) embryonic globin mRNA because of regulation at the transcriptional level. Thus the lineage specificity of embryonic and adult globin gene expression is determined transcriptionally, and the posttranscriptional process described by Landes et al. is a property of the senescing primitive cells, not a mechanism operative in the hemoglobin switch. This conclusion is supported by [ 3 H]leucine incorporation experiments on Percoll-fractionated cells which reveal no posttranscriptional silencing of the embryonic genes during the early stages of the switch. In the course of these studies they have noticed a strong transcriptional pause near the second exon of the globin genes which is induced by 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB) and which resembles a natural pause near that position

Three-dimensional structure and cyanobacterial activity within a desert biological soil crust.

Science.gov (United States)

Raanan, Hagai; Felde, Vincent J M N L; Peth, Stephan; Drahorad, Sylvie; Ionescu, Danny; Eshkol, Gil; Treves, Haim; Felix-Henningsen, Peter; Berkowicz, Simon M; Keren, Nir; Horn, Rainer; Hagemann, Martin; Kaplan, Aaron

2016-02-01

Desert biological soil crusts (BSCs) are formed by adhesion of soil particles to polysaccharides excreted by filamentous cyanobacteria, the pioneers and main producers in this habitat. Biological soil crust destruction is a central factor leading to land degradation and desertification. We study the effect of BSC structure on cyanobacterial activity. Micro-scale structural analysis using X-ray microtomography revealed a vesiculated layer 1.5-2.5 mm beneath the surface in close proximity to the cyanobacterial location. Light profiles showed attenuation with depth of 1%-5% of surface light within 1 mm but also revealed the presence of 'light pockets', coinciding with the vesiculated layer, where the irradiance was 10-fold higher than adjacent crust parts at the same depth. Maximal photosynthetic activity, examined by O2 concentration profiles, was observed 1 mm beneath the surface and another peak in association with the 'light pockets'. Thus, photosynthetic activity may not be visible to currently used remote sensing techniques, suggesting that BSCs' contribution to terrestrial productivity is underestimated. Exposure to irradiance higher than 10% full sunlight diminished chlorophyll fluorescence, whereas O2 evolution and CO2 uptake rose, indicating that fluorescence did not reflect cyanobacterial photosynthetic activity. Our data also indicate that although resistant to high illumination, the BSC-inhabiting cyanobacteria function as 'low-light adapted' organisms. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Genotypic lineages and restriction fragment length polymorphism of canine distemper virus isolates in Thailand.

Science.gov (United States)

Radtanakatikanon, Araya; Keawcharoen, Juthatip; Charoenvisal, Na Taya; Poovorawan, Yong; Prompetchara, Eakachai; Yamaguchi, Ryoji; Techangamsuwan, Somporn

2013-09-27

Canine distemper virus (CDV) is known to cause multisystemic disease in all families of terrestrial carnivores. Attenuated live vaccines have been used to control CDV in a variety of species for many decades, yet a number of CDV infections in vaccinated dogs are still observed. The aims of this study were to investigate the genetic diversity of CDV lineages based on phosphoprotein (P), hemagglutinin (H) and fusion protein (F) genes and to develop the restriction fragment length polymorphism (RFLP) technique for effective differentiation among individual wild-type and vaccine lineages in Thailand. Four commercial vaccine products, thirteen conjunctival swabs and various tissues from 9 necropsied dogs suspected of having CDV infections were included. Virus isolation was performed using Vero cell expressing canine signaling lymphocyte activation molecules (Vero-DST cells). Reverse-transcription polymerase chain reaction (RT-PCR) on 3 gene regions from the dog derived specimens and the vaccines were carried out, then RFLP analysis upon F-gene amplified fragments was developed. Nucleotide sequence and phylogenetic analysis were compared with other CDV lineages in Genbank. Phylogenetic relationships revealed that CDV field isolates were separated from the vaccine lineage and could be divided into two clusters; one of which belonged to the Asia-1 lineage and another, not related to any previous recognized lineages was proposed as 'Asia-4'. RFLP patterns demonstrating concordance with phylogenetic trees of the distemper virus allowed for differentiation between the Asia-1, Asia-4 and vaccine lineages. Thus, RFLP technique is able to effectively distinguish individual wild-type canine distemper virus from vaccine lineages in Thailand. Copyright © 2013 Elsevier B.V. All rights reserved.

[Distribution of abnormal cell clone with deletion of chromosome 20q in marrow cell lineages and apoptosis cells in myelodysplastic syndrome].

Science.gov (United States)

Qin, Ling; Wang, Chun; Qin, You-Wen; Xie, Kuang-Cheng; Yan, Shi-Ke; Gao, Yan-Rong; Wang, Xiao-Rui; Zhao, Chu-Xian

2008-06-01

This study was aimed to investigate the distribution of abnormal clone in marrow cell lineages and apoptosis cells in myelodysplastic syndrome (MDS) with deletion of chromosome 20q. Monoclonal antibodies recognizing myeloid precursors (CD15), erythroid precursors (GPA), T cells (CD3(+)CD56(-)CD16(-)), B cells (CD19), NK cells (CD3(-)CD56(+)CD16(+)) were used to sort bone marrow cells in a MDS patient with del (20q) by fluorescence activated cell sorting (FACS). Annexin V-FITC and PI were used to sort bone marrow Annexin V(+)PI(-) and Annexin V(-)PI(-) cells by FACS. The sorted positive cells were detected by interphase dual-color fluorescence in situ hybridization (D-FISH) using a LSI D20S108 probe (Spectrum Orange) and a Telvysion TM 20p probe (Spectrum Green). FACS and FISH analysis were also performed on the samples from 4 cases with normal karyotype. The results showed that the proportions of MDS clone in the myeloid and erythroid precursors were 70.50% and 93.33% respectively, in the RAEB-1 patient with del (20q) and were obviously higher than that in control group (5.39% and 6.17%). The proportions of abnormal clone in T, B and NK cells were 3.23%, 4.32% and 5.77% respectively and were less than that in control group (5.76%, 4.85%, 6.36%). The percentage of apoptotic cells in the bone marrow nucleated cells was 16.09%. The proportions of MDS clone in Annexin V(+)PI(-) and Annexin V(-)PI(-) cells were 32.48% and 70.11%, respectively. It is concluded that most myeloid and erythroid precursors are originated from the abnormal clone in MDS with del (20q). A little part of apoptotic cells are derived from the abnormal clone.

The antibiotic resistome of free-living and particle-attached bacteria under a reservoir cyanobacterial bloom.

Science.gov (United States)

Guo, Yunyan; Liu, Min; Liu, Lemian; Liu, Xuan; Chen, Huihuang; Yang, Jun

2018-05-04

In freshwater systems, both antibiotic resistance genes (ARGs) and cyanobacterial blooms attract global public health concern. Cyanobacterial blooms can greatly impact bacterial taxonomic communities, but very little is known about the influence of the blooms on antibiotic resistance functional community. In this study, the ARGs in both free-living (FL) and particle-attached (PA) bacteria under bloom and non-bloom conditions were simultaneously investigated in a subtropical reservoir using high-throughput approaches. In total, 145 ARGs and 9 mobile genetic elements (MGEs) were detected. The most diverse and dominant of which (68.93%) were multidrug resistance genes and efflux pump mechanism. The richness of ARGs in both FL and PA bacteria was significantly lower during the bloom period compared with non-bloom period. The abundance of ARGs in FL bacteria was significantly lower under bloom condition than in the non-bloom period, but the abundance of ARGs in PA bacteria stayed constant. More importantly, the resistant functional community in PA bacteria was more strongly influenced by the cyanobacterial bloom than in the FL bacteria, although >96% ARGs were shared in both FL and PA bacteria or both bloom and non-bloom periods. We also compared the community compositions between taxonomy and function, and found antibiotic resistant communities were highly variable and exhibited lower similarity between bloom and non-bloom periods than seen in the taxonomic composition, with an exception of FL bacteria. Altogether, cyanobacterial blooms appear to have stronger inhibitory effect on ARG abundance in FL bacteria, and stronger influence on antibiotic resistant community composition in PA bacteria. Our results further suggested that both neutral and selective processes interactively affected the ARG composition dynamics of the FL and PA bacteria. However, the antibiotic resistant community of FL bacteria exhibited a higher level of temporal stochasticity following the bloom

Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

Science.gov (United States)

Williams, Wendy; Büdel, Burkhard; Williams, Stephen

2018-04-01

The Boodjamulla National Park research station is situated in the north-western Queensland dry savannah, where the climate is dominated by summer monsoons and virtually dry winters. Under shrub canopies and in between the tussock grasses cyanobacterial crusts almost entirely cover the flood plain soil surfaces. Seasonality drives N fixation, and in the savannah this has a large impact on both plant and soil function. Many cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. We examined cyanobacterial species richness and bioavailable N spanning 7 months of a typical wet season. Over the wet season cyanobacterial richness ranged from 6 to 19 species. N-fixing Scytonema accounted for seasonal averages between 51 and 93 % of the biocrust. Cyanobacterial richness was highly correlated with N fixation and bioavailable N in 0-1 cm. Key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N soil enrichment via cyanobacteria would be ˜ 5.2 kg ha-1 annually which is comparable to global averages. This is a substantial contribution to the nutrient-deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N fixation, bioavailable N and C fixation (Büdel et al., 2018) provide important contributions to multifunctional microprocesses and soil fertility.

An overview of cyanobacterial bloom occurrences and research in Africa over the last decade.

Science.gov (United States)

Ndlela, L L; Oberholster, P J; Van Wyk, J H; Cheng, P H

2016-12-01

Cyanobacterial blooms are a current cause for concern globally, with vital water sources experiencing frequent and increasingly toxic blooms in the past decade. These increases are resultant of both anthropogenic and natural factors, with climate change being the central concern. Of the more affected parts of the world, Africa has been considered particularly vulnerable due to its historical predisposition and lag in social economic development. This review collectively assesses the available information on cyanobacterial blooms in Africa as well as any visible trends associated with reported occurrences over the last decade. Of the 54 countries in Africa, only 21 have notable research information in the area of cyanobacterial blooms within the last decade, although there is substantial reason to attribute these blooms as some of the major water quality threats in Africa collectively. The collected information suggests that civil wars, disease outbreaks and inadequate infrastructure are at the core of Africa's delayed advancement. This is even more so in the area of cyanobacteria related research, with 11 out of 21 countries having recorded toxicity and physicochemical parameters related to cyanobacterial blooms. Compared to the rest of the continent, peripheral countries are at the forefront of research related to cyanobacteria, with countries such as Angola having sufficient rainfall, but poor water quality with limited information on bloom occurrences. An assessment of the reported blooms found nitrogen concentrations to be higher in the water column of more toxic blooms, validating recent global studies and indicating that phosphorous is not the only factor to be monitored in bloom mitigation. Blooms occurred at low TN: TP ratios and at temperatures above 12°C. Nitrogen was linked to toxicity and temperature also had a positive effect on bloom occurrence and toxicity. Microcystis was the most ubiquitous of the cyanobacterial strains reported in Africa and the

Health-Based Cyanotoxin Guideline Values Allow for Cyanotoxin-Based Monitoring and Efficient Public Health Response to Cyanobacterial Blooms

Science.gov (United States)

Farrer, David; Counter, Marina; Hillwig, Rebecca; Cude, Curtis

2015-01-01

Human health risks from cyanobacterial blooms are primarily related to cyanotoxins that some cyanobacteria produce. Not all species of cyanobacteria can produce toxins. Those that do often do not produce toxins at levels harmful to human health. Monitoring programs that use identification of cyanobacteria genus and species and enumeration of cyanobacterial cells as a surrogate for cyanotoxin presence can overestimate risk and lead to unnecessary health advisories. In the absence of federal criteria for cyanotoxins in recreational water, the Oregon Health Authority (OHA) developed guideline values for the four most common cyanotoxins in Oregon’s fresh waters (anatoxin-a, cylindrospermopsin, microcystins, and saxitoxins). OHA developed three guideline values for each of the cyanotoxins found in Oregon. Each of the guideline values is for a specific use of cyanobacteria-affected water: drinking water, human recreational exposure and dog recreational exposure. Having cyanotoxin guidelines allows OHA to promote toxin-based monitoring (TBM) programs, which reduce the number of health advisories and focus advisories on times and places where actual, rather than potential, risks to health exist. TBM allows OHA to more efficiently protect public health while reducing burdens on local economies that depend on water recreation-related tourism. PMID:25664510

The history of cyanobacterial blooms in the Baltic Sea.

Science.gov (United States)

Finni, T; Kononen, K; Olsonen, R; Wallström, K

2001-08-01

Long-term information on possible changes in cyanobacterial blooms in the Baltic Sea, formed mainly by Nodularia spumigena and Aphanizomenon sp., was sought in published records in historical (years 1887-1938) and modern (years 1974-1998) phytoplankton data sets. Old and new sampling methods and fixatives were tested to improve the comparison of data that had been collected and analyzed in different ways. A hundred years ago, plankton was mainly of interest as a source of fish food; eutrophication problems were only locally reported from the coast, mainly in southern haffs and the receiving waters of larger cities. There were few recordings of open-sea blooms before World War II. Abundances of Nodularia spumigena and Aphanizomenon sp. were low in the old material, and 137 summer samples from 1887-1938 showed no peak abundance. High abundances are common in the new material, and the range of the numbers of both taxa has increased markedly relative to the old material. Since the 1960s, cyanobacterial blooms have been common in the open sea in both the Baltic proper and the Gulf of Finland, indicating high availability of nutrients.

Exome sequencing of bilateral testicular germ cell tumors suggests independent development lineages.

Science.gov (United States)

Brabrand, Sigmund; Johannessen, Bjarne; Axcrona, Ulrika; Kraggerud, Sigrid M; Berg, Kaja G; Bakken, Anne C; Bruun, Jarle; Fosså, Sophie D; Lothe, Ragnhild A; Lehne, Gustav; Skotheim, Rolf I

2015-02-01

Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs), is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs) or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors), of these three patients in whom both tumors were available (six tumors) and two patients each with only one available tumor (two tumors). Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21), some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA), and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.

Activated macrophages create lineage-specific microenvironments for pancreatic acinar- and β-cell regeneration in mice.

Science.gov (United States)

Criscimanna, Angela; Coudriet, Gina M; Gittes, George K; Piganelli, Jon D; Esni, Farzad

2014-11-01

Although the cells that contribute to pancreatic regeneration have been widely studied, little is known about the mediators of this process. During tissue regeneration, infiltrating macrophages debride the site of injury and coordinate the repair response. We investigated the role of macrophages in pancreatic regeneration in mice. We used a saporin-conjugated antibody against CD11b to reduce the number of macrophages in mice following diphtheria toxin receptor-mediated cell ablation of pancreatic cells, and evaluated the effects on pancreatic regeneration. We analyzed expression patterns of infiltrating macrophages after cell-specific injury or from the pancreas of nonobese diabetic mice. We developed an in vitro culture system to study the ability of macrophages to induce cell-specific regeneration. Depletion of macrophages impaired pancreatic regeneration. Macrophage polarization, as assessed by expression of tumor necrosis factor-α, interleukin 6, interleukin 10, and CD206, depended on the type of injury. The signals provided by polarized macrophages promoted lineage-specific generation of acinar or endocrine cells. Macrophage from nonobese diabetic mice failed to provide signals necessary for β-cell generation. Macrophages produce cell type-specific signals required for pancreatic regeneration in mice. Additional study of these processes and signals might lead to new approaches for treating type 1 diabetes or pancreatitis. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

OpenAIRE

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and li...

Temperature effects explain continental scale distribution of cyanobacterial toxins

OpenAIRE

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and li...

Mycobacterium tuberculosis Lineage 4 comprises globally distributed and geographically restricted sublineages

Science.gov (United States)

Coscolla, Mireia; Liu, Qingyun; Trauner, Andrej; Fenner, Lukas; Rutaihwa, Liliana; Borrell, Sonia; Luo, Tao; Gao, Qian; Kato-Maeda, Midori; Ballif, Marie; Egger, Matthias; Macedo, Rita; Mardassi, Helmi; Moreno, Milagros; Tudo Vilanova, Griselda; Fyfe, Janet; Globan, Maria; Thomas, Jackson; Jamieson, Frances; Guthrie, Jennifer L.; Asante-Poku, Adwoa; Yeboah-Manu, Dorothy; Wampande, Eddie; Ssengooba, Willy; Joloba, Moses; Henry Boom, W.; Basu, Indira; Bower, James; Saraiva, Margarida; Vaconcellos, Sidra E. G.; Suffys, Philip; Koch, Anastasia; Wilkinson, Robert; Gail-Bekker, Linda; Malla, Bijaya; Ley, Serej D.; Beck, Hans-Peter; de Jong, Bouke C.; Toit, Kadri; Sanchez-Padilla, Elisabeth; Bonnet, Maryline; Gil-Brusola, Ana; Frank, Matthias; Penlap Beng, Veronique N.; Eisenach, Kathleen; Alani, Issam; Wangui Ndung’u, Perpetual; Revathi, Gunturu; Gehre, Florian; Akter, Suriya; Ntoumi, Francine; Stewart-Isherwood, Lynsey; Ntinginya, Nyanda E.; Rachow, Andrea; Hoelscher, Michael; Cirillo, Daniela Maria; Skenders, Girts; Hoffner, Sven; Bakonyte, Daiva; Stakenas, Petras; Diel, Roland; Crudu, Valeriu; Moldovan, Olga; Al-Hajoj, Sahal; Otero, Larissa; Barletta, Francesca; Jane Carter, E.; Diero, Lameck; Supply, Philip; Comas, Iñaki; Niemann, Stefan; Gagneux, Sebastien

2016-01-01

Generalist and specialist species differ in the breadth of their ecological niche. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis Lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that Lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that while the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of Lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration. PMID:27798628

Effects of two different high-fidelity DNA polymerases on genetic analysis of the cyanobacterial community structure in a subtropical deep freshwater reservoir

DEFF Research Database (Denmark)

Zhen, Zhuo; Liu, Jingwen; Rensing, Christopher Günther T

2017-01-01

and diversity analysis. In this study, two clone libraries were constructed with two different DNA polymerases, Q5 high-fidelity DNA polymerase and exTaq polymerase, to compare the differences in their capability to accurately reflect the cyanobacterial community structure and diversity in a subtropical deep......-fidelity DNA polymerase. It is noteworthy that so far Q5 high-fidelity DNA polymerase was the first time to be employed in the genetic analysis of cyanobacterial community. And it is for the first time that the cyanobacterial community structure in Dongzhen reservoir was analyzed using molecular methods...

Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

Directory of Open Access Journals (Sweden)

W. Williams

2018-04-01

Full Text Available The Boodjamulla National Park research station is situated in the north-western Queensland dry savannah, where the climate is dominated by summer monsoons and virtually dry winters. Under shrub canopies and in between the tussock grasses cyanobacterial crusts almost entirely cover the flood plain soil surfaces. Seasonality drives N fixation, and in the savannah this has a large impact on both plant and soil function. Many cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. We examined cyanobacterial species richness and bioavailable N spanning 7 months of a typical wet season. Over the wet season cyanobacterial richness ranged from 6 to 19 species. N-fixing Scytonema accounted for seasonal averages between 51 and 93 % of the biocrust. Cyanobacterial richness was highly correlated with N fixation and bioavailable N in 0–1 cm. Key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N soil enrichment via cyanobacteria would be  ∼  5.2 kg ha−1 annually which is comparable to global averages. This is a substantial contribution to the nutrient-deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N fixation, bioavailable N and C fixation (Büdel et al., 2018 provide important contributions to multifunctional microprocesses and soil fertility.

TLX activates MASH1 for induction of neuronal lineage commitment of adult hippocampal neuroprogenitors.

Science.gov (United States)

Elmi, Muna; Matsumoto, Yoshiki; Zeng, Zhao-jun; Lakshminarasimhan, Pavithra; Yang, Weiwen; Uemura, Akiyoshi; Nishikawa, Shin-ichi; Moshiri, Alicia; Tajima, Nobuyoshi; Agren, Hans; Funa, Keiko

2010-10-01

The orphan nuclear receptor TLX has been proposed to act as a repressor of cell cycle inhibitors to maintain the neural stem cells in an undifferentiated state, and prevents commitment into astrocyte lineages. However, little is known about the mechanism of TLX in neuronal lineage commitment and differentiation. A majority of adult rat hippocampus-derived progenitors (AHPs) cultured in the presence of FGF express a high level of TLX and a fraction of these cells also express the proneural gene MASH1. Upon FGF withdrawal, TLX rapidly decreased, while MASH1 was intensely expressed within 1h, decreasing gradually to disappear at 24h. Adenoviral transduction of TLX in AHP cells in the absence of FGF transiently increased cell proliferation, however, later resulted in neuronal differentiation by inducing MASH1, Neurogenin1, DCX, and MAP2ab. Furthermore, TLX directly targets and activates the MASH1 promoter through interaction with Sp1, recruiting co-activators whereas dismissing the co-repressor HDAC4. Conversely, silencing of TLX in AHPs decreased beta-III tubulin and DCX expression and promoted glial differentiation. Our results thus suggest that TLX not only acts as a repressor of cell cycle and glial differentiation but also activates neuronal lineage commitment in AHPs. Copyright 2010 Elsevier Inc. All rights reserved.

Development of immobilized cyanobacterial amendments for reclamation of microbiotic soil crusts

Czech Academy of Sciences Publication Activity Database

Kubečková, Klára; Johansen, J. R.; Warren, S. D.; Sparks, R.

2003-01-01

Roč. 148, č. 109 (2003), s. 341-362 ISSN 0342-1120. [Symposium of the International Association for Cyanophyte Research/15./. Barcelona, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR KSK6005114 Keywords : cyanobacteria * cyanobacterial amendments * desert soil Subject RIV: EF - Botanics

Characterization of the cyanobacterial biocenosis of a freshwater reservoir in Italy

Czech Academy of Sciences Publication Activity Database

Mugnai, M. A.; Turicchia, S.; Margheri, M. C.; Sili, C.; Gugger, M.; Tedioli, G.; Komárek, Jiří; Ventura, S.

2003-01-01

Roč. 148, č. 109 (2003), s. 403-419 ISSN 0342-1120. [Symposium of the International Association for Cyanophyte Research /15./. Barcelona, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR KSK6005114 Keywords : freshwater reservoir * cyanobacterial diversity * morphology Subject RIV: EF - Botanics

Factors Released from Endothelial Cells Exposed to Flow Impact Adhesion, Proliferation, and Fate Choice in the Adult Neural Stem Cell Lineage.

Science.gov (United States)

Dumont, Courtney M; Piselli, Jennifer M; Kazi, Nadeem; Bowman, Evan; Li, Guoyun; Linhardt, Robert J; Temple, Sally; Dai, Guohao; Thompson, Deanna M

2017-08-15

The microvasculature within the neural stem cell (NSC) niche promotes self-renewal and regulates lineage progression. Previous work identified endothelial-produced soluble factors as key regulators of neural progenitor cell (NPC) fate and proliferation; however, endothelial cells (ECs) are sensitive to local hemodynamics, and the effect of this key physiological process has not been defined. In this study, we evaluated adult mouse NPC response to soluble factors isolated from static or dynamic (flow) EC cultures. Endothelial factors generated under dynamic conditions significantly increased neuronal differentiation, while those released under static conditions stimulated oligodendrocyte differentiation. Flow increases EC release of neurogenic factors and of heparin sulfate glycosaminoglycans that increase their bioactivity, likely underlying the enhanced neuronal differentiation. Additionally, endothelial factors, especially from static conditions, promoted adherent growth. Together, our data suggest that blood flow may impact proliferation, adhesion, and the neuron-glial fate choice of adult NPCs, with implications for diseases and aging that reduce flow.

Pathology of fatal lineage 1 and 2 West Nile virus infections in horses in South Africa

Directory of Open Access Journals (Sweden)

June H. Williams

2014-09-01

Full Text Available Since 2007, West Nile virus (WNV has been reported in South African horses, causing severe neurological signs. All cases were of lineage 2, except for one case that clustered with lineage 1 viruses. In the present study, gross and microscopic lesions of six South African lineage 2-infected horses and the one lineage 1 case are described. Diagnoses were confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR of central nervous system (CNS tissue and one by RT-PCR of a brain virus isolate. The CNS of all cases was negative by RT-PCR or immunohistochemistry (IHC for African horse sickness (AHS, equine encephalosis virus, equine herpes viruses 1 and 4, other zoonotic flaviviruses, alphaviruses, and shunivirus, and either by immunofluorescence or IHC for rabies. Gross visceral lesions were nonspecific but often mimicked those of AHS. The CNS histopathology of WNV lineage 2 cases resembled the nonsuppurative polioencephalomyelitis reported in the Northern Hemisphere lineage 1 and recent Hungarian lineage 2 cases. Occasional meningitis, focal spinal ventral horn poliomalacia, dorsal and lateral horn poliomyelitis, leucomyelitis, asymmetrical ventral motor spinal neuritis and frequent olfactory region involvement were also seen. Lineage 2 cases displayed marked variations in CNS lesion severity, type and distribution, and suggested various viral entry routes into the CNS, based on findings in experimental mice and hamsters. Lineage 1 lesions were comparable to the milder lineage 2 cases. West Nile virus IHC on CNS sections with marked lesions from all cases elicited only two antigen-positive cells in the olfactory cortex of one case. The presence in the CNS of T-lymphocytes, B-lymphocytes, plasma cells and macrophage-monocytes was confirmed by cluster of differentiation (CD 3, CD20, multiple myeloma oncogene 1 (MUM1 and macrophage (MAC 387 IHC.

Estimates of global cyanobacterial biomass and its distribution

Science.gov (United States)

Garcia-Pichel, Ferran; Belnap, Jayne; Neuer, Susanne; Schanz, Ferdinand

2003-01-01

We estimated global cyanobacterial biomass in the main reservoirs of cyanobacteria on Earth: marine and freshwater plankton, arid land soil crusts, and endoliths. Estimates were based on typical population density values as measured during our research, or as obtained from literature surveys, which were then coupled with data on global geographical area coverage. Among the marine plankton, the global biomass of Prochlorococcus reaches 120 × 1012 grams of carbon (g C), and that of Synechoccus some 43 × 1012 g C. This makes Prochlorococcus and Synechococcus, in that order, the most abundant cyanobacteria on Earth. Tropical marine blooms of Trichodesmium account for an additional 10 × 1012 g C worldwide. In terrestrial environments, the mass of cyanobacteria in arid land soil crusts is estimated to reach 54 × 1012 g C and that of arid land endolithic communities an additional 14 × 1012 g C. The global biomass of planktic cyanobacteria in lakes is estimated to be around 3 × 1012 g C. Our conservative estimates, which did not include some potentially significant biomass reservoirs such as polar and subarctic areas, topsoils in subhumid climates, and shallow marine and freshwater benthos, indicate that the total global cyanobacterial biomass is in the order of 3 × 1014 g C, surpassing a thousand million metric tons (1015 g) of wet biomass.

Catchment-fed cyanobacterial blooms in brownified temperate lakes

Science.gov (United States)

Senar, O.; Creed, I. F.

2017-12-01

One of the most significant impacts of global atmospheric change is the alteration of hydrological regimes and the associated disruption of hydrological connectivity within watersheds. We show how changes in the frequency, magnitude, and duration of hydrological connectivity and disconnectivity is compromising the capacity of forest soils to store organic carbon, and increasing its export to both aquatic and atmospheric systems. Increases in dissolved organic matter (DOM) loads from forested landscapes to aquatic systems and the shift of the DOM pool to a more refractory mixture of organic compounds, a process known as brownification, alters the physical and chemical characteristics of lake environments. Furthermore, by characterizing the stages of brownification (from low to high concentrations of refractory DOM), we show a shift in the limiting factors for phytoplankton growth from macronutrients (nitrogen -N- and phosphorus -P) to micronutrients (iron -Fe) and light availability. This shift is driven by the low concentrations of DOM supplying N and P in early stages of brownification, to the strong Fe-binding capacity of refractory DOM in brownified lakes. As lakes undergo brownification, cyanobacteria adapted to scavenge Fe from DOM-Fe complexes have a competitive advantage leading to the formation of cyanobacterial blooms. Our findings provide evidence that brownification is a driving force leading to cyanobacterial blooms in lakes on forested landscapes, with expected cascading consequences to lake food webs.

Visualisation of chicken macrophages using transgenic reporter genes: insights into the development of the avian macrophage lineage.

Science.gov (United States)

Balic, Adam; Garcia-Morales, Carla; Vervelde, Lonneke; Gilhooley, Hazel; Sherman, Adrian; Garceau, Valerie; Gutowska, Maria W; Burt, David W; Kaiser, Pete; Hume, David A; Sang, Helen M

2014-08-01

We have generated the first transgenic chickens in which reporter genes are expressed in a specific immune cell lineage, based upon control elements of the colony stimulating factor 1 receptor (CSF1R) locus. The Fms intronic regulatory element (FIRE) within CSF1R is shown to be highly conserved in amniotes and absolutely required for myeloid-restricted expression of fluorescent reporter genes. As in mammals, CSF1R-reporter genes were specifically expressed at high levels in cells of the macrophage lineage and at a much lower level in granulocytes. The cell lineage specificity of reporter gene expression was confirmed by demonstration of coincident expression with the endogenous CSF1R protein. In transgenic birds, expression of the reporter gene provided a defined marker for macrophage-lineage cells, identifying the earliest stages in the yolk sac, throughout embryonic development and in all adult tissues. The reporter genes permit detailed and dynamic visualisation of embryonic chicken macrophages. Chicken embryonic macrophages are not recruited to incisional wounds, but are able to recognise and phagocytose microbial antigens. © 2014. Published by The Company of Biologists Ltd.

Effect of 17-allylamino-17-demethoxygeldanamycin (17-AAG) on Akt protein expression is more effective in head and neck cancer cell lineages that retain PTEN protein expression.

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Pontes, Flávia Sirotheau C; Pontes, Hélder A R; de Souza, Lucas L; de Jesus, Adriana S; Joaquim, Andrea M C; Miyahara, Ligia A N; Fonseca, Felipe P; Pinto Junior, Décio S

2018-03-01

The aim of this study was to evaluate the expression of Akt, PTEN, Mdm2 and p53 proteins in three different head and neck squamous cell carcinoma (HNSCC) cell lines (HN6, HN19 and HN30), all of them treated with epidermal growth factor (EGF) and 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of Hsp90 protein. Immunofluorescence and western blot were performed in order to analyze the location and quantification, respectively, of proteins under the action 17-AAG and EGF. Treatment with EGF resulted in increased levels of Akt, PTEN and p53 in all cell lineages. The expression of Mdm2 was constant in HN30 and HN6 lineages, while in HN19 showed slightly decreased expression. Under the action 17-AAG, in HN6 and HN19, the expression of PTEN and p53 proteins was suppressed, while Akt and Mdm2 expression was reduced. Finally, in the HN30 cell lineage were absolute absence of expression of Akt, Mdm2 and p53 and decreased expression of PTEN. These data allow us to speculate on the particular utility of 17-AAG for HNSCC treatment through the inhibition of Akt protein expression, especially in the cases that retain the expression of PTEN protein. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The 3'UTR of nanos2 directs enrichment in the germ cell lineage of the sea urchin.

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Oulhen, Nathalie; Yoshida, Takaya; Yajima, Mamiko; Song, Jia L; Sakuma, Tetsushi; Sakamoto, Naoaki; Yamamoto, Takashi; Wessel, Gary M

2013-05-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells during embryogenesis. Three nanos homologs are present in the genome of the sea urchin Strongylocentrotus purpuratus (Sp), and each nanos mRNA accumulates specifically in the small micromere (sMic) lineage. We found that a highly conserved element in the 3' UTR of nanos2 is sufficient for reporter expression selectively in the sMic lineage: microinjection into a Sp fertilized egg of an RNA that contains the GFP open reading frame followed by Sp nanos2 3'UTR leads to selective reporter enrichment in the small micromeres in blastulae. The same result was seen with nanos2 from the sea urchin Hemicentrotus pulcherrimus (Hp). In both species, the 5'UTR alone is not sufficient for the sMic localization but it always increased the sMic reporter enrichment when present with the 3'UTR. We defined an element conserved between Hp and Sp in the nanos2 3'UTR which is necessary and sufficient for protein enrichment in the sMic, and refer to it as GNARLE (Global Nanos Associated RNA Lability Element). We also found that the nanos2 3'UTR is essential for the selective RNA retention in the small micromeres; GNARLE is required but not sufficient for this process. These results show that a combination of selective RNA retention and translational control mechanisms instills nanos accumulation uniquely in the sMic lineage. Copyright © 2013 Elsevier Inc. All rights reserved.

Cyanobacterial pigments as natural anti-hyperglycemic agents: An in vitro study

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Tonmoy Ghosh

2016-08-01

Full Text Available Traditional medicines for controlling postprandial hyperglycemia includes herbs and plant extracts as well as synthetic drugs like acarbose. Synthetic drug molecules frequently have side effects such as flatulence and diarrhea. Cyanobacterial pigments have excellent anti-oxidant and free radical scavenging properties. Thus, α-amylase and α-glucosidase inhibiting activities of purified pigments and crude extracts from three cyanobacterial species, Lyngbya, Microcoleus and Synechocystis sp., were investigated. Lyngbya extract had the highest total anti-oxidant activity (TAC before digestion (48.26 ± 0.04 µg AAE ml-1 while purified lycopene had the highest TAC after digestion (154.16 ± 0.96 µg AAE ml-1. The Microcoleus extract had the highest ABTS scavenging activity before digestion (98.23 ± 0.25 % while purified C-phycocyanin (C-PC had the highest ABTS scavenging after digestion (99.69 ±0.04 %. None of the digested or undigested extracts performed better than acarbose in inhibiting α-amylase but the digested Microcoleus extract was able to inhibit its activity by ~35 %. The purified pigments gave inhibitory activities ranging from ~ 8 – 16 %. The Lyngbya extract had the highest inhibitory activity against α-glucosidase both before and after digestion (62.22 ± 0.02 and 97.82 ± 0.03 % respectively. Purified C-phycoerythrin (C-PE, C-PC, lycopene and myxoxanthophyll could inhibit α-glucosidase in a range of ~83 – 96 %. Considering the potent inhibitory activities of purified pigments against both α-amylase and α-glucosidase, cyanobacterial pigments could be used as food additives for their dual advantage of anti-oxidant and anti-hyperglycemic activities.

Accumulation of cyanobacterial toxins in freshwater 'seafood' and its consequences for public health: A review

Energy Technology Data Exchange (ETDEWEB)

Ibelings, Bas W. [Eawag, Swiss Federal Institute of Aquatic Sciences and Technology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum (Switzerland); Netherlands Institute of Ecology, Centre for Limnology, Rijksstraatweg 6, 3631 AC, Nieuwersluis (Netherlands)], E-mail: bas.ibelings@eawag.ch; Chorus, Ingrid [German Federal Environment Agency, Corrensplatz 1, 14195 Berlin (Germany)], E-mail: ingrid.chorus@uba.de

2007-11-15

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in 'seafood' collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and the likelihood of bioaccumulation discussed; (b) we derive cyanotoxin doses likely to occur through seafood consumption and propose guideline values for seafood and compare these to guidelines for drinking water; and (c) we discuss means to assess, control or mitigate the risks of exposure to cyanotoxins through seafood consumption. This is discussed in the context of two specific procedures, the food specific HACCP-approach and the water-specific Water Safety Plan approach by the WHO. Risks of exposure to cyanotoxins in food are sometimes underestimated. Risk assessments should acknowledge this and investigate the partitioning of exposure between drinking-water and food, which may vary depending on local circumstances. - Accumulation of cyanobacterial toxins in freshwater 'seafood'.

Review of 130 years of research on cyanobacteria in aquatic ecosystems in Serbia presented in a Serbian Cyanobacterial Database

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Zorica Svirčev

2017-05-01

Full Text Available The presence of toxic cyanobacteria in aquatic ecosystems in the territory of the Republic of Serbia was surveyed over a period of several decades. Increasing attention is being paid to some negative consequences that may be caused by these microorganisms. Information from available literary sources regarding the distribution and frequency of cyanobacteria and their toxins over a period of 130 years, together with the effects on humans and wildlife in aquatic ecosystems, were gathered and incorporated into a Serbian Cyanobacterial Database created for the CYANOCOST Action. This database encompasses information on 65 aquatic ecosystems, including rivers, lakes, ponds, canals, irrigation reservoirs, reservoirs used for drinking water supply and reservoirs used for other purposes. Cyanobacterial blooms were found in almost 80% of the investigated aquatic ecosystems. The analysis of the research showed the presence of more than 70 species, including blooms of 24 species from 13 genera. Five species of cyanobacteria: Microcystis aeruginosa, Aphanizomenon flos-aquae, Planktothrix agardhii, Microcystis flos-aquae and Planktothrix rubescens frequently formed blooms in the investigated waterbodies and cyanotoxins were also detected in some of them, which had certain negative effects. Here, we present an overview of data contained in the Serbian Cyanobacterial Database, concerning cyanobacterial distribution, cyanotoxin production and associated biological effects in different types of water bodies from the Republic of Serbia. Also, recent important and major cases of cyanobacterial blooming in reservoirs used for drinking water supply: at Vrutci and Ćelije, the Aleksandrovac irrigation reservoir, the Ponjavica River and Lake Palić, including systematic research on the Lake Ludoš and few fishponds are further described. It can be concluded that cyanobacteria and cyanotoxins are omnipresent in different water bodies throughout the Republic of Serbia

Observations of volatile organic compounds over the North Atlantic Ocean: relationships to dominant cyanobacterial populations.

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Swarthout, R.; Rossell, R.; Sive, B. C.; Zhou, Y.; Reddy, C. M.; Valentine, D. L.; Cox, D.

2017-12-01

Marine cyanobacteria are abundant primary producers that can have a major influence on the oceanic biogeochemical cycles. In particular, the prominent cyanobacterial genera Prochlorococcus, Synechococcus, and Trichodesmium can impact the air-sea flux of volatile organic compounds (VOCs) including reactive compounds, such as isoprene, that control the oxidative capacity of the atmosphere and climate-relevant compounds, such as dimethyl sulfide. These groups of cyanobacteria have been estimated to increase in abundance by up to 29% by the end of the century as a result of rising sea surface temperatures and dissolved carbon dioxide concentrations. Given their current and predicted future abundance, understanding the role of different cyanobacterial populations on VOC emissions from the ocean is critical in understanding the future oxidative capacity of the remote atmosphere and climate feedback cycles. During the May 2017 Phosphorus, Hydrocarbons, and Transcriptomics cruise aboard the R/V Neil Armstrong, 160 whole air canister samples were collected along a transect through the North Atlantic from Woods Hole, MA to Bermuda and back with 24-hour stops at nine stations encompassing different nutrient regimes and cyanobacterial populations. At each station, a diurnal time series of samples was collected and higher frequency sampling was conducted during transits of the north wall. Canister samples were analyzed on a five-detector gas chromatography system for over 80 individual VOCs including biogenics, aromatics, chlorinated and brominated compounds, and sulfur containing compounds. Trends in reactive and climate-relevant VOCs will be discussed as a function of the predominant cyanobacterial populations at each sample location. These data provide increased information on the spatial and diurnal variability of trace gases associated with these globally important photosynthetic cyanobacteria.

Activation of GSK3β by Sirt2 is required for early lineage commitment of mouse embryonic stem cell.

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Xiaoxing Si

Full Text Available Sirt2, a member of the NAD(+-dependent protein deacetylase family, is increasingly recognized as a critical regulator of the cell cycle, cellular necrosis and cytoskeleton organization. However, its role in embryonic stem cells (ESCs remains unclear. Here we demonstrate that Sirt2 is up-regulated during RA (retinoic acid-induced and embryoid body (EB differentiation of mouse ESCs. Using lentivirus-mediated shRNA methods, we found that knockdown of Sirt2 compromises the differentiation of mouse ESCs into ectoderm while promoting mesoderm and endoderm differentiation. Knockdown of Sirt2 expression also leads to the activation of GSK3β through decreased phosphorylation of the serine at position 9 (Ser9 but not tyrosine at position 216 (Tyr216. Moreover, the constitutive activation of GSK3β during EB differentiation mimics the effect of Sirt2 knockdown, while down-regulation of GSK3β rescues the effect of Sirt2 knockdown on differentiation. In contrast to the effect on lineage differentiation, Sirt2 knockdown and GSK3β up-regulation do not change the self-renewal state of mouse ESCs. Overall, our report reveals a new function for Sirt2 in regulating the proper lineage commitment of mouse ESCs.

Cyanobacterial diversity in extreme environments in Baja California, Mexico: a polyphasic study.

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López-Cortés, A; García-Pichel, F; Nübel, U; Vázquez-Juárez, R

2001-12-01

Cyanobacterial diversity from two geographical areas of Baja California Sur, Mexico, were studied: Bahia Concepcion, and Ensenada de Aripez. The sites included hypersaline ecosystems, sea bottom, hydrothermal springs, and a shrimp farm. In this report we describe four new morphotypes, two are marine epilithic from Bahia Concepcion, Dermocarpa sp. and Hyella sp. The third, Geitlerinema sp., occurs in thermal springs and in shrimp ponds, and the fourth, Tychonema sp., is from a shrimp pond. The partial sequences of the 16S rRNA genes and the phylogenetic relationship of four cyanobacterial strains (Synechococcus cf. elongatus, Leptolyngbya cf. thermalis, Leptolyngbya sp., and Geitlerinema sp.) are also presented. Polyphasic studies that include the combination of light microscopy, cultures and the comparative analysis of 16S rRNA gene sequences provide the most powerful approach currently available to establish the diversity of these oxygenic photosynthetic microorganisms in culture and in nature.

Defining the cellular lineage hierarchy in the interfollicular epidermis of adult skin.

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Sada, Aiko; Jacob, Fadi; Leung, Eva; Wang, Sherry; White, Brian S; Shalloway, David; Tumbar, Tudorita

2016-06-01

The interfollicular epidermis regenerates from heterogeneous basal skin cell populations that divide at different rates. It has previously been presumed that infrequently dividing basal cells known as label-retaining cells (LRCs) are stem cells, whereas non-LRCs are short-lived progenitors. Here we employ the H2B-GFP pulse-chase system in adult mouse skin and find that epidermal LRCs and non-LRCs are molecularly distinct and can be differentiated by Dlx1(CreER) and Slc1a3(CreER) genetic marking, respectively. Long-term lineage tracing and mathematical modelling of H2B-GFP dilution data show that LRCs and non-LRCs constitute two distinct stem cell populations with different patterns of proliferation, differentiation and upward cellular transport. During homeostasis, these populations are enriched in spatially distinct skin territories and can preferentially produce unique differentiated lineages. On wounding or selective killing, they can temporarily replenish each other's territory. These two discrete interfollicular stem cell populations are functionally interchangeable and intrinsically well adapted to thrive in distinct skin environments.

Comparison of Chlorella vulgaris and cyanobacterial biomass: cultivation in urban wastewater and methane production.

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Mendez, Lara; Sialve, Bruno; Tomás-Pejó, Elia; Ballesteros, Mercedes; Steyer, Jean Philippe; González-Fernández, Cristina

2016-05-01

Anaerobic digestion of microalgae is hampered by its complex cell wall. Against this background, cyanobacteria cell walls render this biomass as an ideal substrate for overcoming this drawback. The aim of the present study was to compare the growth of two cyanobacteria (Aphanizomenon ovalisporum and Anabaena planctonica) and a microalga (Chlorella vulgaris) in urban wastewater when varying the temperature (22, 27 and 32 °C). Cyanobacterial optimal growth for both strains was attained at 22 °C, while C. vulgaris did not show remarkable differences among temperatures. For all the microorganisms, ammonium removal was higher than phosphate. Biomass collected was subjected to anaerobic digestion. Methane yield of C. vulgaris was 184.8 mL CH4 g COD in(-1) while with A. ovalisporum and A. planctonica the methane production was 1.2- and 1.4-fold higher. This study showed that cyanobacteria growth rates could be comparable to microalgae while presenting the additional benefit of an increased anaerobic digestibility.

Feasibility study on production of a matrix reference material for cyanobacterial toxins.

Science.gov (United States)

Hollingdale, Christie; Thomas, Krista; Lewis, Nancy; Békri, Khalida; McCarron, Pearse; Quilliam, Michael A

2015-07-01

The worldwide increase in cyanobacterial contamination of freshwater lakes and rivers is of great concern as many cyanobacteria produce potent hepatotoxins and neurotoxins (cyanotoxins). Such toxins pose a threat to aquatic ecosystems, livestock, and drinking water supplies. In addition, dietary supplements prepared from cyanobacteria can pose a risk to consumers if they contain toxins. Analytical monitoring for toxins in the environment and in consumer products is essential for the protection of public health. Reference materials (RMs) are an essential tool for the development and validation of analytical methods and are necessary for ongoing quality control of monitoring operations. Since the availability of appropriate RMs for cyanotoxins has been very limited, the present study was undertaken to examine the feasibility of producing a cyanobacterial matrix RM containing various cyanotoxins. The first step was large-scale culturing of various cyanobacterial cultures that produce anatoxins, microcystins, and cylindrospermopsins. After harvesting, the biomass was lyophilized, blended, homogenized, milled, and bottled. The moisture content and physical characteristics were assessed in order to evaluate the effectiveness of the production process. Toxin levels were measured by liquid chromatography with tandem mass spectrometry and ultraviolet detection. The reference material was found to be homogeneous for toxin content. Stability studies showed no significant degradation of target toxins over a period of 310 days at temperatures up to +40 °C except for the anatoxin-a, which showed some degradation at +40 °C. These results show that a fit-for-purpose matrix RM for cyanotoxins can be prepared using the processes and techniques applied in this work.

Organic matter degradation drives benthic cyanobacterial mat abundance on caribbean coral reefs

NARCIS (Netherlands)

Brocke, Hannah J.; Polerecky, Lubos; De Beer, Dirk; Weber, Miriam; Claudet, Joachim; Nugues, Maggy M.

2015-01-01

Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised

In vivo and in vitro expression of myeloid antigens on B-lineage acute lymphoblastic leukemia cells.

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Hara, J; Kawa-Ha, K; Yumura-Yagi, K; Kurahashi, H; Tawa, A; Ishihara, S; Inoue, M; Murayama, N; Okada, S

1991-01-01

The expression of myeloid antigens has been extensively examined using two-color analysis in 43 children with B-lineage acute lymphoblastic leukemia (ALL). On pre-culture cells, CD33 expression was frequently observed in CD19+, CD10- B-precursor ALL, and CD14 was expressed only on the cells from B-precursor ALL expressing CD19, CD10 and CD20, and B-ALL. After 2 or 3 days of culture without TPA, CD13 emerged on the cells from 21 of 29 patients irrespective of the presence or the absence of fetal calf serum in the culture. Of four patients with CD10+ B-precursor ALL, which showed no expression of CD13 after culture, two had T-cell associated antigens. Whereas the addition of TPA to the culture enhanced the expression of CD13 on the cells from acute non-lymphocytic leukemia (ANLL), TPA reduced the expression of this antigen on B-precursor cells. These findings suggest that the regulatory mechanism of CD13 expression may be different between B-precursor ALL and ANLL. Co-culture with cycloheximide mostly abrogated the induction of CD13, suggesting that CD13 expression was mainly dependent on de novo protein synthesis.

Correlations between cyanobacterial density and bacterial transformation to the viable but nonculturable (VBNC) state in four freshwater water bodies.

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Chen, Huirong; Shen, Ju; Pan, Gaoshan; Liu, Jing; Li, Jiancheng; Hu, Zhangli

2015-10-01

Nutrient concentrations, phytoplankton density and community composition, and the viable but nonculturable (VBNC) state of heterotrophic bacteria were investigated in three connected reservoirs and a small isolated lake in South China to study the relationship between biotic and abiotic factors and the VBNC state in bacteria. Nutrient concentrations in the reservoirs increased in the direction of water flow, whereas Wenshan Lake was more eutrophic. Cyanobacterial blooms occurred in all four water bodies, with differing seasonal trends and dominant species. In Xili and Tiegang Reservoirs, the VBNC ratio (percent of VBNC state bacteria over total viable bacteria) was high for most of the year and negatively correlated with cyanobacterial density. Laboratory co-culture experiments were performed with four heterotrophic bacterial species isolated from Wenshan Lake (Escherichia coli, Klebsiella peneumoniae, Bacillus megaterium and Bacillus cereus) and the dominant cyanobacterial species (Microcystis aeruginosa). For the first three bacterial species, the presence of M. aeruginosa induced the VBNC state and the VBNC ratio was positively correlated with M. aeruginosa density. However, B. cereus inhibited M. aeruginosa growth. These results demonstrate that cyanobacteria could potentially regulate the transformation to the VBNC state of waterborne bacteria, and suggest a role for bacteria in cyanobacterial bloom initiation and termination.

Concise classification of the genomic porcine endogenous retroviral gamma1 load to defined lineages.

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Klymiuk, Nikolai; Wolf, Eckhard; Aigner, Bernhard

2008-02-05

We investigated the infection history of porcine endogenous retroviruses (PERV) gamma1 by analyzing published env and LTR sequences. PERV sequences from various breeds, porcine cell lines and infected human primary cells were included in the study. We identified a considerable number of retroviral lineages indicating multiple independent colonization events of the porcine genome. A recent boost of the proviral load in an isolated pig herd and exclusive occurrence of distinct lineages in single studies indicated the ongoing colonization of the porcine genome with endogenous retroviruses. Retroviral recombination between co-packaged genomes was a general factor for PERV gamma1 diversity which indicated the simultaneous expression of different proviral loci over a period of time. In total, our detailed description of endogenous retroviral lineages is the prerequisite for breeding approaches to minimize the infectious potential of porcine tissues for the subsequent use in xenotransplantation.

Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA in Shark Fins

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John Pablo

2012-02-01

Full Text Available Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA.

Occurrence and elimination of cyanobacterial toxins in drinking water treatment plants

International Nuclear Information System (INIS)

Hoeger, Stefan J.; Hitzfeld, Bettina C.; Dietrich, Daniel R.

2005-01-01

Toxin-producing cyanobacteria (blue-green algae) are abundant in surface waters used as drinking water resources. The toxicity of one group of these toxins, the microcystins, and their presence in surface waters used for drinking water production has prompted the World Health Organization (WHO) to publish a provisional guideline value of 1.0 μg microcystin (MC)-LR/l drinking water. To verify the efficiency of two different water treatment systems with respect to reduction of cyanobacterial toxins, the concentrations of MC in water samples from surface waters and their associated water treatment plants in Switzerland and Germany were investigated. Toxin concentrations in samples from drinking water treatment plants ranged from below 1.0 μg MC-LR equiv./l to more than 8.0 μg/l in raw water and were distinctly below 1.0 μg/l after treatment. In addition, data to the worldwide occurrence of cyanobacteria in raw and final water of water works and the corresponding guidelines for cyanobacterial toxins in drinking water worldwide are summarized

THE TRPV1 RECEPTOR: THE INTERAGENCY, INTERNATION SYMPOSIUM ON CYANOBACTERIAL HARMFUL ALGAL BLOOMS.

Science.gov (United States)

Background and Significance Evidence indicates that the frequency of occurrence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial and temporal extent in the US and worldwide. Cyanotoxins are among the most potent toxins known, causing death through ...

Uncovering the mutation-fixation correlation in short lineages

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Vallender Eric J

2007-09-01

Full Text Available Abstract Background We recently reported a highly unexpected positive correlation between the fixation probability of nonsynonymous mutations (estimated by ω and neutral mutation rate (estimated by Ks in mammalian lineages. However, this positive correlation was observed for lineages with relatively long divergence time such as the human-mouse lineage, and was not found for very short lineages such as the human-chimpanzee lineage. It was previously unclear how to interpret this discrepancy. It may indicate that the positive correlation between ω and Ks in long lineages is a false finding. Alternatively, it may reflect a biologically meaningful difference between various lineages. Finally, the lack of positive correlation in short lineages may be the result of methodological artifacts. Results Here we show that a strong positive correlation can indeed be seen in short lineages when a method was introduced to correct for the inherently high levels of stochastic noise in the use of Ks as an estimator of neutral mutation rate. Thus, the previously noted lack of positive correlation between ω and Ks in short lineages is due to stochastic noise in Ks that makes it a far less reliable estimator of neutral mutation rate in short lineages as compared to long lineages. Conclusion A positive correlation between ω and Ks can be observed in all mammalian lineages for which large amounts of sequence data are available, including very short lineages. It confirms the authenticity of this highly unexpected correlation, and argues that the correction likely applies broadly across all mammals and perhaps even non-mammalian species.

Lineage tracing of lamellocytes demonstrates Drosophila macrophage plasticity.

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Martin Stofanko

2010-11-01

Full Text Available Leukocyte-like cells called hemocytes have key functions in Drosophila innate immunity. Three hemocyte types occur: plasmatocytes, crystal cells, and lamellocytes. In the absence of qimmune challenge, plasmatocytes are the predominant hemocyte type detected, while crystal cells and lamellocytes are rare. However, upon infestation by parasitic wasps, or in melanotic mutant strains, large numbers of lamellocytes differentiate and encapsulate material recognized as "non-self". Current models speculate that lamellocytes, plasmatocytes and crystal cells are distinct lineages that arise from a common prohemocyte progenitor. We show here that over-expression of the CoREST-interacting transcription factor Chn in plasmatocytes induces lamellocyte differentiation, both in circulation and in lymph glands. Lamellocyte increases are accompanied by the extinction of plasmatocyte markers suggesting that plasmatocytes are transformed into lamellocytes. Consistent with this, timed induction of Chn over-expression induces rapid lamellocyte differentiation within 18 hours. We detect double-positive intermediates between plasmatocytes and lamellocytes, and show that isolated plasmatocytes can be triggered to differentiate into lamellocytes in vitro, either in response to Chn over-expression, or following activation of the JAK/STAT pathway. Finally, we have marked plasmatocytes and show by lineage tracing that these differentiate into lamellocytes in response to the Drosophila parasite model Leptopilina boulardi. Taken together, our data suggest that lamellocytes arise from plasmatocytes and that plasmatocytes may be inherently plastic, possessing the ability to differentiate further into lamellocytes upon appropriate challenge.

Prevention of Cyanobacterial Blooms Using Nanosilica: A Biomineralization-Inspired Strategy.

Science.gov (United States)

Xiong, Wei; Tang, Yiming; Shao, Changyu; Zhao, Yueqi; Jin, Biao; Huang, Tingting; Miao, Ya'nan; Shu, Lei; Ma, Weimin; Xu, Xurong; Tang, Ruikang

2017-11-07

Cyanobacterial blooms represent a significant threat to global water resources because blooming cyanobacteria deplete oxygen and release cyanotoxins, which cause the mass death of aquatic organisms. In nature, a large biomass volume of cyanobacteria is a precondition for a bloom, and the cyanobacteria buoyancy is a key parameter for inducing the dense accumulation of cells on the water surface. Therefore, blooms will likely be curtailed if buoyancy is inhibited. Inspired by diatoms with naturally generated silica shells, we found that silica nanoparticles can be spontaneously incorporated onto cyanobacteria in the presence of poly(diallyldimethylammonium chloride), a cationic polyelectrolyte that can simulate biosilicification proteins. The resulting cyanobacteria-SiO 2 complexes can remain sedimentary in water. This strategy significantly inhibited the photoautotrophic growth of the cyanobacteria and decreased their biomass accumulation, which could effectively suppress harmful bloom events. Consequently, several of the adverse consequences of cyanobacteria blooms in water bodies, including oxygen consumption and microcystin release, were significantly alleviated. Based on the above results, we propose that the silica nanoparticle treatment has the potential for use as an efficient strategy for preventing cyanobacteria blooms.

Emerging health issues of cyanobacterial blooms

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Maura Manganelli

2012-12-01

Full Text Available This paper describes emerging issue related to cyanobacterial dynamics and toxicity and human health risks. Data show an increasing cyanobacteria expansion and dominance in many environments. However there are still few information on the toxic species fitness, or on the effects of specific drivers on toxin production. Open research fields are related to new exposure scenario (cyanotoxins in water used for haemodialysis and in food supplements; to new patterns of co-exposure between cyanotoxins and algal toxins and/or anthropogenic chemicals; to dynamics affecting toxicity and production of different cyanotoxin variants under environmental stress; to the accumulation of cyanotoxins in the food web. In addition, many data gaps exist in the characterization of the toxicological profiles, especially about long term effects.

The 3’UTR of Nanos2 directs enrichment in the germ cell lineage of the sea urchin

Science.gov (United States)

Oulhen, Nathalie; Yoshida, Takaya; Yajima, Mamiko; Song, Jia; Sakuma, Tetsushi; Sakamoto, Naoaki; Yamamoto, Takashi; Wessel, Gary M.

2013-01-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells during embryogenesis. Three nanos homologs are present in the genome of the sea urchin Strongylocentrotus purpuratus (Sp), and each nanos mRNA accumulates specifically in the small micromere (sMic) lineage. We found that a highly conserved element in the 3’ UTR of nanos2 is sufficient for reporter expression selectively in the sMic lineage: microinjection into a Sp fertilized egg of an RNA that contains the GFP open reading frame followed by Sp nanos2 3’UTR leads to selective reporter enrichment in the small micromeres in blastulae. The same result was seen with nanos2 from the sea urchin Hemicentrotus pulcherrimus (Hp). In both species, the 5’UTR alone is not sufficient for the sMic localization but it always increased the sMic reporter enrichment when present with the 3’UTR. We defined an element conserved between Hp and Sp in the nanos2 3’UTR which is necessary and sufficient for protein enrichment in the sMic, and refer to it as GNARLE (Global Nanos Associated RNA Lability Element). We also found that the nanos2 3’UTR is essential for the selective RNA retention in the small micromeres; GNARLE is required but not sufficient for this process. These results show that a combination of selective RNA retention and translational control mechanisms instills nanos accumulation uniquely in the sMic lineage. PMID:23357540

Frequency of inhibitors of daphnid trypsin in the widely distributed cyanobacterial genus Planktothrix

DEFF Research Database (Denmark)

Rohrlack, T.; Christoffersen, K.; Friberg-Jensen, U.

2005-01-01

on the frequency of such compounds in the widely distributed cyanobacterial genus Planktothrix. Of the 89 Planktothrix strains analysed, about 70% produced inhibitors of daphnid trypsin. The strains tested positive represented three common Planktothrix species and were isolated from diverse localities...

Stem cell plasticity.

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Lakshmipathy, Uma; Verfaillie, Catherine

2005-01-01

The central dogma in stem cell biology has been that cells isolated from a particular tissue can renew and differentiate into lineages of the tissue it resides in. Several studies have challenged this idea by demonstrating that tissue specific cell have considerable plasticity and can cross-lineage restriction boundary and give rise to cell types of other lineages. However, the lack of a clear definition for plasticity has led to confusion with several reports failing to demonstrate that a single cell can indeed differentiate into multiple lineages at significant levels. Further, differences between results obtained in different labs has cast doubt on some results and several studies still await independent confirmation. In this review, we critically evaluate studies that report stem cell plasticity using three rigid criteria to define stem cell plasticity; differentiation of a single cell into multiple cell lineages, functionality of differentiated cells in vitro and in vivo, robust and persistent engraft of transplanted cells.

Risk to human health associated with the environmental occurrence of cyanobacterial neurotoxic alkaloids anatoxins and saxitoxins.

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Testai, Emanuela; Scardala, Simona; Vichi, Susanna; Buratti, Franca M; Funari, Enzo

2016-01-01

Cyanobacteria are ubiquitous photosynthetic micro-organisms forming blooms and scums in surface water; among them some species can produce cyanotoxins giving rise to some concern for human health and animal life. To date, more than 65 cyanobacterial neurotoxins have been described, of which the most studied are the groups of anatoxins and saxitoxins (STXs), comprising many different variants. In freshwaters, the hepatotoxic microcystins represent the most frequently detected cyanotoxin: on this basis, it could appear that neurotoxins are less relevant, but the low frequency of detection may partially reflect an a priori choice of target analytes, the low method sensitivity and the lack of certified standards. Cyanobacterial neurotoxins target cholinergic synapses or voltage-gated ion channels, blocking skeletal and respiratory muscles, thus leading to death by respiratory failure. This review reports and analyzes the available literature data on environmental occurrence of cyanobacterial neurotoxic alkaloids, namely anatoxins and STXs, their biosynthesis, toxicology and epidemiology, derivation of guidance values and action limits. These data are used as the basis to assess the risk posed to human health, identify critical exposure scenarios and highlight the major data gaps and research needs.

Direct lineage reprogramming of mouse fibroblasts to functional midbrain dopaminergic neuronal progenitors

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Han-Seop Kim

2014-01-01

Full Text Available The direct lineage reprogramming of somatic cells to other lineages by defined factors has led to innovative cell-fate-change approaches for providing patient-specific cells. Recent reports have demonstrated that four pluripotency factors (Oct4, Sox2, Klf4, and c-Myc are sufficient to directly reprogram fibroblasts to other specific cells, including induced neural stem cells (iNSCs. Here, we show that mouse fibroblasts can be directly reprogrammed into midbrain dopaminergic neuronal progenitors (DPs by temporal expression of the pluripotency factors and environment containing sonic hedgehog and fibroblast growth factor 8. Within thirteen days, self-renewing and functional induced DPs (iDPs were generated. Interestingly, the inhibition of both Jak and Gsk3β notably enhanced the iDP reprogramming efficiency. We confirmed the functionality of the iDPs by showing that the dopaminergic neurons generated from iDPs express midbrain markers, release dopamine, and show typical electrophysiological profiles. Our results demonstrate that the pluripotency factors-mediated direct reprogramming is an invaluable strategy for supplying functional and proliferating iDPs and may be useful for other neural progenitors required for disease modeling and cell therapies for neurodegenerative disorders.

Loss of C/EBP alpha cell cycle control increases myeloid progenitor proliferation and transforms the neutrophil granulocyte lineage

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Porse, Bo T; Bryder, David; Theilgaard-Mönch, Kim

2005-01-01

dissociate the ability of C/EBP alpha to block cell cycle progression through E2F inhibition from its function as a transcriptional activator impair the in vivo development of the neutrophil granulocyte and adipose lineages. We now show that such mutations increase the capacity of bone marrow (BM) myeloid...... progenitors to proliferate, and predispose mice to a granulocytic myeloproliferative disorder and transformation of the myeloid compartment of the BM. Both of these phenotypes were transplantable into lethally irradiated recipients. BM transformation was characterized by a block in granulocyte differentiation...

State of knowledge and concerns on cyanobacterial blooms and cyanotoxins.

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Merel , Sylvain; Walker , David; Chicana , Ruth; Snyder , Shane; Baurès , Estelle; Thomas , Olivier

2013-01-01

International audience; Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surf...

Autoantigens targeted in scleroderma patients with vascular disease are enriched in endothelial lineage cells

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McMahan, Zsuzsanna H.; Cottrell, Tricia R.; Wigley, Fredrick M.; Antiochos, Brendan; Zambidis, Elias T.; Park, Tea Soon; Halushka, Marc K.; Gutierrez-Alamillo, Laura; Cimbro, Raffaello; Rosen, Antony; Casciola-Rosen, Livia

2016-01-01

Objective Scleroderma patients with autoantibodies to centromere proteins (CENPs) and/or interferon-inducible protein 16 (IFI16) are at increased risk of severe vascular complications. We set out to define whether these autoantigens are enriched in cells of the vasculature. Methods Successive stages of embryoid bodies (EBs) as well as vascular progenitors were used to evaluate the expression of scleroderma autoantigens IFI16 and CENP by immunoblotting. CD31 was included to mark early blood vessels. IFI16 and CD31 expression were defined in skin paraffin sections from scleroderma patients and from healthy controls. IFI16 expression was determined by flow cytometry in circulating endothelial cells (CECs) and circulating progenitor cells (CPCs). Results Expression of CENP-A, IFI16 and CD31 was enriched in EBs at days 10 and 12 of differentiation, and particularly in cultures enriched in vascular progenitors (IFI16, CD31, CENPs A and-B). This pattern was distinct from that of comparator autoantigens. Immunohistochemical staining of skin paraffin sections showed enrichment of IFI16 in CD31-positive vascular endothelial cells in biopsies from scleroderma patients and normal controls. Flow cytometry analysis revealed IFI16 expression in CPCs, but minimal expression in CECs. Conclusion Expression of scleroderma autoantigens IFI16 and CENPs, which are associated with severe vascular disease, is increased in vascular progenitors and mature endothelial cells. High level, lineage-enriched expression of autoantigens may explain the striking association between clinical phenotypes and the immune targeting of specific autoantigens. PMID:27159521

Pharmacogenomic identification of small molecules for lineage specific manipulation of subventricular zone germinal activity.

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Kasum Azim

2017-03-01

Full Text Available Strategies for promoting neural regeneration are hindered by the difficulty of manipulating desired neural fates in the brain without complex genetic methods. The subventricular zone (SVZ is the largest germinal zone of the forebrain and is responsible for the lifelong generation of interneuron subtypes and oligodendrocytes. Here, we have performed a bioinformatics analysis of the transcriptome of dorsal and lateral SVZ in early postnatal mice, including neural stem cells (NSCs and their immediate progenies, which generate distinct neural lineages. We identified multiple signaling pathways that trigger distinct downstream transcriptional networks to regulate the diversity of neural cells originating from the SVZ. Next, we used a novel in silico genomic analysis, searchable platform-independent expression database/connectivity map (SPIED/CMAP, to generate a catalogue of small molecules that can be used to manipulate SVZ microdomain-specific lineages. Finally, we demonstrate that compounds identified in this analysis promote the generation of specific cell lineages from NSCs in vivo, during postnatal life and adulthood, as well as in regenerative contexts. This study unravels new strategies for using small bioactive molecules to direct germinal activity in the SVZ, which has therapeutic potential in neurodegenerative diseases.

Targeting CD147 for T to NK Lineage Reprogramming and Tumor Therapy.

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Geng, Jie-Jie; Tang, Juan; Yang, Xiang-Min; Chen, Ruo; Zhang, Yang; Zhang, Kui; Miao, Jin-Lin; Chen, Zhi-Nan; Zhu, Ping

2017-06-01

CD147 is highly expressed on the surface of numerous tumor cells to promote invasion and metastasis. Targeting these cells with CD147-specific antibodies has been validated as an effective approach for lung and liver cancer therapy. In the immune system, CD147 is recognized as a co-stimulatory receptor and impacts the outcome of thymic selection. Using T cell-specific deletion, we showed here that in thymus CD147 is indispensable for the stable αβ T cell lineage commitment: loss of CD147 biases both multipotent DN (double negative) and fully committed DP (double positive) cells into innate NK-like lineages. Mechanistically, CD147 deficiency results in impaired Wnt signaling and expression of BCL11b, a master transcription factor in determining T cell identity. In addition, functional blocking of CD147 by antibody phenocopies genetic deletion to enrich NK-like cells in the periphery. Furthermore, using a melanoma model and orthotopic liver cancer transplants, we showed that the augmentation of NK-like cells strongly associates with resistance against tumor growth upon CD147 suppression. Therefore, besides its original function in tumorigenesis, CD147 is also an effective surface target for immune modulation in tumor therapy. Copyright © 2017. Published by Elsevier B.V.

Targeting CD147 for T to NK Lineage Reprogramming and Tumor Therapy

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Jie-Jie Geng

2017-06-01

Full Text Available CD147 is highly expressed on the surface of numerous tumor cells to promote invasion and metastasis. Targeting these cells with CD147-specific antibodies has been validated as an effective approach for lung and liver cancer therapy. In the immune system, CD147 is recognized as a co-stimulatory receptor and impacts the outcome of thymic selection. Using T cell-specific deletion, we showed here that in thymus CD147 is indispensable for the stable αβ T cell lineage commitment: loss of CD147 biases both multipotent DN (double negative and fully committed DP (double positive cells into innate NK-like lineages. Mechanistically, CD147 deficiency results in impaired Wnt signaling and expression of BCL11b, a master transcription factor in determining T cell identity. In addition, functional blocking of CD147 by antibody phenocopies genetic deletion to enrich NK-like cells in the periphery. Furthermore, using a melanoma model and orthotopic liver cancer transplants, we showed that the augmentation of NK-like cells strongly associates with resistance against tumor growth upon CD147 suppression. Therefore, besides its original function in tumorigenesis, CD147 is also an effective surface target for immune modulation in tumor therapy.

Cytolethal distending toxin: a conserved bacterial genotoxin that blocks cell cycle progression, leading to apoptosis of a broad range of mammalian cell lineages.

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Jinadasa, Rasika N; Bloom, Stephen E; Weiss, Robert S; Duhamel, Gerald E

2011-07-01

Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important Gram-negative mucocutaneous bacterial pathogens. Irrespective of the bacterial species of origin, CDT causes characteristic and irreversible cell cycle arrest and apoptosis in a broad range of cultured mammalian cell lineages. The active subunit CdtB has structural homology with the phosphodiesterase family of enzymes including mammalian DNase I, and alone is necessary and sufficient to account for cellular toxicity. Indeed, mammalian cells treated with CDT initiate a DNA damage response similar to that elicited by ionizing radiation-induced DNA double strand breaks resulting in cell cycle arrest and apoptosis. The mechanism of CDT-induced apoptosis remains incompletely understood, but appears to involve both p53-dependent and -independent pathways. While epithelial, endothelial and fibroblast cell lines respond to CDT by undergoing arrest of cell cycle progression resulting in nuclear and cytoplasmic distension that precedes apoptotic cell death, cells of haematopoietic origin display rapid apoptosis following a brief period of cell cycle arrest. In this review, the ecology of pathogens producing CDT, the molecular biology of bacterial CDT and the molecular mechanisms of CDT-induced cytotoxicity are critically appraised. Understanding the contribution of a broadly conserved bacterial genotoxin that blocks progression of the mammalian cell cycle, ultimately causing cell death, should assist with elucidating disease mechanisms for these important pathogens.

Comparative single-cell genomics reveals potential ecological niches for the freshwater acI Actinobacteria lineage.

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Ghylin, Trevor W; Garcia, Sarahi L; Moya, Francisco; Oyserman, Ben O; Schwientek, Patrick; Forest, Katrina T; Mutschler, James; Dwulit-Smith, Jeffrey; Chan, Leong-Keat; Martinez-Garcia, Manuel; Sczyrba, Alexander; Stepanauskas, Ramunas; Grossart, Hans-Peter; Woyke, Tanja; Warnecke, Falk; Malmstrom, Rex; Bertilsson, Stefan; McMahon, Katherine D

2014-12-01

Members of the acI lineage of Actinobacteria are the most abundant microorganisms in most freshwater lakes; however, our understanding of the keys to their success and their role in carbon and nutrient cycling in freshwater systems has been hampered by the lack of pure cultures and genomes. We obtained draft genome assemblies from 11 single cells representing three acI tribes (acI-A1, acI-A7, acI-B1) from four temperate lakes in the United States and Europe. Comparative analysis of acI SAGs and other available freshwater bacterial genomes showed that acI has more gene content directed toward carbohydrate acquisition as compared to Polynucleobacter and LD12 Alphaproteobacteria, which seem to specialize more on carboxylic acids. The acI genomes contain actinorhodopsin as well as some genes involved in anaplerotic carbon fixation indicating the capacity to supplement their known heterotrophic lifestyle. Genome-level differences between the acI-A and acI-B clades suggest specialization at the clade level for carbon substrate acquisition. Overall, the acI genomes appear to be highly streamlined versions of Actinobacteria that include some genes allowing it to take advantage of sunlight and N-rich organic compounds such as polyamines, di- and oligopeptides, branched-chain amino acids and cyanophycin. This work significantly expands the known metabolic potential of the cosmopolitan freshwater acI lineage and its ecological and genetic traits.

Lineage Reprogramming of Astroglial Cells from Different Origins into Distinct Neuronal Subtypes

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Malek Chouchane

2017-07-01

Full Text Available Astroglial cells isolated from the rodent postnatal cerebral cortex are particularly susceptible to lineage reprogramming into neurons. However, it remains unknown whether other astroglial populations retain the same potential. Likewise, little is known about the fate of induced neurons (iNs in vivo. In this study we addressed these questions using two different astroglial populations isolated from the postnatal brain reprogrammed either with Neurogenin-2 (Neurog2 or Achaete scute homolog-1 (Ascl1. We show that cerebellum (CerebAstro and cerebral cortex astroglia (CtxAstro generates iNs with distinctive neurochemical and morphological properties. Both astroglial populations contribute iNs to the olfactory bulb following transplantation in the postnatal and adult mouse subventricular zone. However, only CtxAstro transfected with Neurog2 differentiate into pyramidal-like iNs after transplantation in the postnatal cerebral cortex. Altogether, our data indicate that the origin of the astroglial population and transcription factors used for reprogramming, as well as the region of integration, affect the fate of iNs.

Developmental fate and lineage commitment of singled mouse blastomeres.

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Lorthongpanich, Chanchao; Doris, Tham Puay Yoke; Limviphuvadh, Vachiranee; Knowles, Barbara B; Solter, Davor

2012-10-01

The inside-outside model has been invoked to explain cell-fate specification of the pre-implantation mammalian embryo. Here, we investigate whether cell-cell interaction can influence the fate specification of embryonic blastomeres by sequentially separating the blastomeres in two-cell stage mouse embryos and continuing separation after each cell division throughout pre-implantation development. This procedure eliminates information provided by cell-cell interaction and cell positioning. Gene expression profiles, polarity protein localization and functional tests of these separated blastomeres reveal that cell interactions, through cell position, influence the fate of the blastomere. Blastomeres, in the absence of cell contact and inner-outer positional information, have a unique pattern of gene expression that is characteristic of neither inner cell mass nor trophectoderm, but overall they have a tendency towards a 'trophectoderm-like' gene expression pattern and preferentially contribute to the trophectoderm lineage.

AMPK governs lineage specification through Tfeb-dependent regulation of lysosomes.

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Young, Nathan P; Kamireddy, Anwesh; Van Nostrand, Jeanine L; Eichner, Lillian J; Shokhirev, Maxim Nikolaievich; Dayn, Yelena; Shaw, Reuben J

2016-03-01

Faithful execution of developmental programs relies on the acquisition of unique cell identities from pluripotent progenitors, a process governed by combinatorial inputs from numerous signaling cascades that ultimately dictate lineage-specific transcriptional outputs. Despite growing evidence that metabolism is integrated with many molecular networks, how pathways that control energy homeostasis may affect cell fate decisions is largely unknown. Here, we show that AMP-activated protein kinase (AMPK), a central metabolic regulator, plays critical roles in lineage specification. Although AMPK-deficient embryonic stem cells (ESCs) were normal in the pluripotent state, these cells displayed profound defects upon differentiation, failing to generate chimeric embryos and preferentially adopting an ectodermal fate at the expense of the endoderm during embryoid body (EB) formation. AMPK(-/-) EBs exhibited reduced levels of Tfeb, a master transcriptional regulator of lysosomes, leading to diminished endolysosomal function. Remarkably, genetic loss of Tfeb also yielded endodermal defects, while AMPK-null ESCs overexpressing this transcription factor normalized their differential potential, revealing an intimate connection between Tfeb/lysosomes and germ layer specification. The compromised endolysosomal system resulting from AMPK or Tfeb inactivation blunted Wnt signaling, while up-regulating this pathway restored expression of endodermal markers. Collectively, these results uncover the AMPK pathway as a novel regulator of cell fate determination during differentiation. © 2016 Young et al.; Published by Cold Spring Harbor Laboratory Press.

Investigational Antibody-Drug Conjugates for Treatment of B-lineage Malignancies.

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Herrera, Alex F; Molina, Arturo

2018-05-10

Antibody-drug conjugates (ADCs) are tripartite molecules consisting of a monoclonal antibody, a covalent linker, and a cytotoxic payload. ADC development has aimed to target the specificity inherent in antigen-antibody interactions to deliver potent cytotoxins preferentially to tumor cells and maximize antitumor activity and simultaneously minimize off-target toxicity. The earliest ADCs provided disappointing results in the clinic; however, the lessons learned regarding the need for human or humanized antibodies, more stable linkers, and greater potency payloads led to improved ADCs. Three ADCs, gemtuzumab ozogamicin, brentuximab vedotin (BV), and inotuzumab ozogamicin, have been approved for hematologic malignancies. Site-specific conjugation methods have now resulted in a new generation of more uniform, molecularly defined ADCs. These are expected to display improved in vivo properties and have recently entered the clinic. We reviewed investigational ADCs currently in clinical testing for the treatment of B-cell lineage malignancies, including leukemias, lymphomas, and multiple myeloma. The rationales for antigen targeting, data reported to date, current trial status, and preclinical results for several newer ADCs expected to enter first-in-human studies are presented. Owing to the large number of ongoing and reported BV clinical studies, only the studies of BV for diffuse large B-cell lymphoma and those combining BV with checkpoint inhibitors in B-lineage malignancies have been reviewed. With > 40 ongoing clinical trials and 7 investigational ADCs already having advanced to phase II studies, the role of ADCs in the armamentarium for the treatment of B-lineage malignancies continues to be elucidated. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

The genome and structural proteome of an ocean siphovirus: a new window into the cyanobacterial 'mobilome'.

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Sullivan, Matthew B; Krastins, Bryan; Hughes, Jennifer L; Kelly, Libusha; Chase, Michael; Sarracino, David; Chisholm, Sallie W

2009-11-01

Prochlorococcus, an abundant phototroph in the oceans, are infected by members of three families of viruses: myo-, podo- and siphoviruses. Genomes of myo- and podoviruses isolated on Prochlorococcus contain DNA replication machinery and virion structural genes homologous to those from coliphages T4 and T7 respectively. They also contain a suite of genes of cyanobacterial origin, most notably photosynthesis genes, which are expressed during infection and appear integral to the evolutionary trajectory of both host and phage. Here we present the first genome of a cyanobacterial siphovirus, P-SS2, which was isolated from Atlantic slope waters using a Prochlorococcus host (MIT9313). The P-SS2 genome is larger than, and considerably divergent from, previously sequenced siphoviruses. It appears most closely related to lambdoid siphoviruses, with which it shares 13 functional homologues. The approximately 108 kb P-SS2 genome encodes 131 predicted proteins and notably lacks photosynthesis genes which have consistently been found in other marine cyanophage, but does contain 14 other cyanobacterial homologues. While only six structural proteins were identified from the genome sequence, 35 proteins were detected experimentally; these mapped onto capsid and tail structural modules in the genome. P-SS2 is potentially capable of integration into its host as inferred from bioinformatically identified genetic machinery int, bet, exo and a 53 bp attachment site. The host attachment site appears to be a genomic island that is tied to insertion sequence (IS) activity that could facilitate mobility of a gene involved in the nitrogen-stress response. The homologous region and a secondary IS-element hot-spot in Synechococcus RS9917 are further evidence of IS-mediated genome evolution coincident with a probable relic prophage integration event. This siphovirus genome provides a glimpse into the biology of a deep-photic zone phage as well as the ocean cyanobacterial prophage and IS element

Lipocalin-2 inhibits osteoclast formation by suppressing the proliferation and differentiation of osteoclast lineage cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun-Ju, E-mail: biohjk@knu.ac.kr [Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Yoon, Hye-Jin [Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Yoon, Kyung-Ae [Department of Orthopedic Surgery, Skeletal Diseases Genome Research Center, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Gwon, Mi-Ri; Jin Seong, Sook [Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Suk, Kyoungho [Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Kim, Shin-Yoon [Department of Orthopedic Surgery, Skeletal Diseases Genome Research Center, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Yoon, Young-Ran, E-mail: yry@knu.ac.kr [Department of Molecular Medicine, Cell and Matrix Research Institute, Clinical Trial Center, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of)

2015-06-10

Lipocalin-2 (LCN2) is a member of the lipocalin superfamily and plays a critical role in the regulation of various physiological processes, such as inflammation and obesity. In this study, we report that LCN2 negatively modulates the proliferation and differentiation of osteoclast precursors, resulting in impaired osteoclast formation. The overexpression of LCN2 in bone marrow-derived macrophages or the addition of recombinant LCN2 protein inhibits the formation of multinuclear osteoclasts. LCN2 suppresses macrophage colony-stimulating factor (M-CSF)-induced proliferation of osteoclast precursor cells without affecting their apoptotic cell death. Interestingly, LCN2 decreases the expression of the M-CSF receptor, c-Fms, and subsequently blocks its downstream signaling cascades. In addition, LCN2 inhibits RANKL-induced osteoclast differentiation and attenuates the expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1), which are important modulators in osteoclastogenesis. Mechanistically, LCN2 inhibits NF-κB signaling pathways, as demonstrated by the suppression of IκBα phosphorylation, nuclear translocation of p65, and NF-κB transcriptional activity. Thus, LCN2 is an anti-osteoclastogenic molecule that exerts its effects by retarding the proliferation and differentiation of osteoclast lineage cells. - Highlights: • LCN2 expression is regulated during osteoclast development. • LCN2 suppresses M-CSF-mediated osteoclast precursor proliferation. • LCN2 inhibits RANKL-induced osteoclast differentiation.

Dual small-molecule targeting of SMAD signaling stimulates human induced pluripotent stem cells toward neural lineages.

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Methichit Wattanapanitch

Full Text Available Incurable neurological disorders such as Parkinson's disease (PD, Huntington's disease (HD, and Alzheimer's disease (AD are very common and can be life-threatening because of their progressive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases, we generated induced pluripotent stem cells (iPSCs from human dermal fibroblasts (HDFs and then differentiated them into neural progenitor cells (NPCs and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor, valproic acid (VPA, and inhibitor of p160-Rho associated coiled-coil kinase (ROCK, Y-27632, after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology, cell surface antigens, pluripotency-associated gene and protein expressions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542, inhibitors of the SMAD signaling pathway, HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction, neuroepithelial cells (NEPCs were observed in the adherent monolayer culture, which had the ability to differentiate further into NPCs and neurons, as characterized by their morphology and the expression of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity assays.

Feedback, Lineages and Self-Organizing Morphogenesis.

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Sameeran Kunche

2016-03-01

Full Text Available Feedback regulation of cell lineage progression plays an important role in tissue size homeostasis, but whether such feedback also plays an important role in tissue morphogenesis has yet to be explored. Here we use mathematical modeling to show that a particular feedback architecture in which both positive and negative diffusible signals act on stem and/or progenitor cells leads to the appearance of bistable or bi-modal growth behaviors, ultrasensitivity to external growth cues, local growth-driven budding, self-sustaining elongation, and the triggering of self-organization in the form of lamellar fingers. Such behaviors arise not through regulation of cell cycle speeds, but through the control of stem or progenitor self-renewal. Even though the spatial patterns that arise in this setting are the result of interactions between diffusible factors with antagonistic effects, morphogenesis is not the consequence of Turing-type instabilities.

Feedback, Lineages and Self-Organizing Morphogenesis

Science.gov (United States)

Calof, Anne L.; Lowengrub, John S.; Lander, Arthur D.

2016-01-01

Feedback regulation of cell lineage progression plays an important role in tissue size homeostasis, but whether such feedback also plays an important role in tissue morphogenesis has yet to be explored. Here we use mathematical modeling to show that a particular feedback architecture in which both positive and negative diffusible signals act on stem and/or progenitor cells leads to the appearance of bistable or bi-modal growth behaviors, ultrasensitivity to external growth cues, local growth-driven budding, self-sustaining elongation, and the triggering of self-organization in the form of lamellar fingers. Such behaviors arise not through regulation of cell cycle speeds, but through the control of stem or progenitor self-renewal. Even though the spatial patterns that arise in this setting are the result of interactions between diffusible factors with antagonistic effects, morphogenesis is not the consequence of Turing-type instabilities. PMID:26989903

Epilithic Cyanobacterial Communities of a Marine Tropical Beach Rock (Heron Island, Great Barrier Reef): Diversity and Diazotrophy▿

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Díez, Beatriz; Bauer, Karolina; Bergman, Birgitta

2007-01-01

The diversity and nitrogenase activity of epilithic marine microbes in a Holocene beach rock (Heron Island, Great Barrier Reef, Australia) with a proposed biological calcification “microbialite” origin were examined. Partial 16S rRNA gene sequences from the dominant mat (a coherent and layered pink-pigmented community spread over the beach rock) and biofilms (nonstratified, differently pigmented microbial communities of small shallow depressions) were retrieved using denaturing gradient gel electrophoresis (DGGE), and a clone library was retrieved from the dominant mat. The 16S rRNA gene sequences and morphological analyses revealed heterogeneity in the cyanobacterial distribution patterns. The nonheterocystous filamentous genus Blennothrix sp., phylogenetically related to Lyngbya, dominated the mat together with unidentified nonheterocystous filaments of members of the Pseudanabaenaceae and the unicellular genus Chroococcidiopsis. The dominance and three-dimensional intertwined distribution of these organisms were confirmed by nonintrusive scanning microscopy. In contrast, the less pronounced biofilms were dominated by the heterocystous cyanobacterial genus Calothrix, two unicellular Entophysalis morphotypes, Lyngbya spp., and members of the Pseudanabaenaceae family. Cytophaga-Flavobacterium-Bacteroides and Alphaproteobacteria phylotypes were also retrieved from the beach rock. The microbial diversity of the dominant mat was accompanied by high nocturnal nitrogenase activities (as determined by in situ acetylene reduction assays). A new DGGE nifH gene optimization approach for cyanobacterial nitrogen fixers showed that the sequences retrieved from the dominant mat were related to nonheterocystous uncultured cyanobacterial phylotypes, only distantly related to sequences of nitrogen-fixing cultured cyanobacteria. These data stress the occurrence and importance of nonheterocystous epilithic cyanobacteria, and it is hypothesized that such epilithic cyanobacteria

Extracting Fluorescent Reporter Time Courses of Cell Lineages from High-Throughput Microscopy at Low Temporal Resolution

Science.gov (United States)

Downey, Mike J.; Jeziorska, Danuta M.; Ott, Sascha; Tamai, T. Katherine; Koentges, Georgy; Vance, Keith W.; Bretschneider, Till

2011-01-01

The extraction of fluorescence time course data is a major bottleneck in high-throughput live-cell microscopy. Here we present an extendible framework based on the open-source image analysis software ImageJ, which aims in particular at analyzing the expression of fluorescent reporters through cell divisions. The ability to track individual cell lineages is essential for the analysis of gene regulatory factors involved in the control of cell fate and identity decisions. In our approach, cell nuclei are identified using Hoechst, and a characteristic drop in Hoechst fluorescence helps to detect dividing cells. We first compare the efficiency and accuracy of different segmentation methods and then present a statistical scoring algorithm for cell tracking, which draws on the combination of various features, such as nuclear intensity, area or shape, and importantly, dynamic changes thereof. Principal component analysis is used to determine the most significant features, and a global parameter search is performed to determine the weighting of individual features. Our algorithm has been optimized to cope with large cell movements, and we were able to semi-automatically extract cell trajectories across three cell generations. Based on the MTrackJ plugin for ImageJ, we have developed tools to efficiently validate tracks and manually correct them by connecting broken trajectories and reassigning falsely connected cell positions. A gold standard consisting of two time-series with 15,000 validated positions will be released as a valuable resource for benchmarking. We demonstrate how our method can be applied to analyze fluorescence distributions generated from mouse stem cells transfected with reporter constructs containing transcriptional control elements of the Msx1 gene, a regulator of pluripotency, in mother and daughter cells. Furthermore, we show by tracking zebrafish PAC2 cells expressing FUCCI cell cycle markers, our framework can be easily adapted to different cell

Extracting fluorescent reporter time courses of cell lineages from high-throughput microscopy at low temporal resolution.

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Mike J Downey

Full Text Available The extraction of fluorescence time course data is a major bottleneck in high-throughput live-cell microscopy. Here we present an extendible framework based on the open-source image analysis software ImageJ, which aims in particular at analyzing the expression of fluorescent reporters through cell divisions. The ability to track individual cell lineages is essential for the analysis of gene regulatory factors involved in the control of cell fate and identity decisions. In our approach, cell nuclei are identified using Hoechst, and a characteristic drop in Hoechst fluorescence helps to detect dividing cells. We first compare the efficiency and accuracy of different segmentation methods and then present a statistical scoring algorithm for cell tracking, which draws on the combination of various features, such as nuclear intensity, area or shape, and importantly, dynamic changes thereof. Principal component analysis is used to determine the most significant features, and a global parameter search is performed to determine the weighting of individual features. Our algorithm has been optimized to cope with large cell movements, and we were able to semi-automatically extract cell trajectories across three cell generations. Based on the MTrackJ plugin for ImageJ, we have developed tools to efficiently validate tracks and manually correct them by connecting broken trajectories and reassigning falsely connected cell positions. A gold standard consisting of two time-series with 15,000 validated positions will be released as a valuable resource for benchmarking. We demonstrate how our method can be applied to analyze fluorescence distributions generated from mouse stem cells transfected with reporter constructs containing transcriptional control elements of the Msx1 gene, a regulator of pluripotency, in mother and daughter cells. Furthermore, we show by tracking zebrafish PAC2 cells expressing FUCCI cell cycle markers, our framework can be easily adapted

Rapid and specific detection of Asian- and African-lineage Zika viruses.

Science.gov (United States)

Chotiwan, Nunya; Brewster, Connie D; Magalhaes, Tereza; Weger-Lucarelli, James; Duggal, Nisha K; Rückert, Claudia; Nguyen, Chilinh; Garcia Luna, Selene M; Fauver, Joseph R; Andre, Barb; Gray, Meg; Black, William C; Kading, Rebekah C; Ebel, Gregory D; Kuan, Guillermina; Balmaseda, Angel; Jaenisch, Thomas; Marques, Ernesto T A; Brault, Aaron C; Harris, Eva; Foy, Brian D; Quackenbush, Sandra L; Perera, Rushika; Rovnak, Joel

2017-05-03

Understanding the dynamics of Zika virus transmission and formulating rational strategies for its control require precise diagnostic tools that are also appropriate for resource-poor environments. We have developed a rapid and sensitive loop-mediated isothermal amplification (LAMP) assay that distinguishes Zika viruses of Asian and African lineages. The assay does not detect chikungunya virus or flaviviruses such as dengue, yellow fever, or West Nile viruses. The assay conditions allowed direct detection of Zika virus RNA in cultured infected cells; in mosquitoes; in virus-spiked samples of human blood, plasma, saliva, urine, and semen; and in infected patient serum, plasma, and semen samples without the need for RNA isolation or reverse transcription. The assay offers rapid, specific, sensitive, and inexpensive detection of the Asian-lineage Zika virus strain that is currently circulating in the Western hemisphere, and can also detect the African-lineage Zika virus strain using separate, specific primers. Copyright © 2017, American Association for the Advancement of Science.

Rapid and specific detection of Asian- and African-lineage Zika viruses

Science.gov (United States)

Chotiwan, Nunya; Brewster, Connie D.; Magalhaes, Tereza; Weger-Lucarelli, James; Duggal, Nisha K.; Rückert, Claudia; Nguyen, Chilinh; Garcia Luna, Selene M.; Fauver, Joseph R.; Andre, Barb; Gray, Meg; Black, William C.; Kading, Rebekah C.; Ebel, Gregory D.; Kuan, Guillermina; Balmaseda, Angel; Jaenisch, Thomas; Marques, Ernesto T. A.; Brault, Aaron C.; Harris, Eva; Foy, Brian D.; Quackenbush, Sandra L.; Perera, Rushika; Rovnak, Joel

2017-01-01

Understanding the dynamics of Zika virus transmission and formulating rational strategies for its control require precise diagnostic tools that are also appropriate for resource-poor environments. We have developed a rapid and sensitive loop-mediated isothermal amplification (LAMP) assay that distinguishes Zika viruses of Asian and African lineages. The assay does not detect chikungunya virus or flaviviruses such as dengue, yellow fever, or West Nile viruses. The assay conditions allowed direct detection of Zika virus RNA in cultured infected cells; in mosquitoes; in virus-spiked samples of human blood, plasma, saliva, urine, and semen; and in infected patient serum, plasma, and semen samples without the need for RNA isolation or reverse transcription. The assay offers rapid, specific, sensitive, and inexpensive detection of the Asian-lineage Zika virus strain that is currently circulating in the Western hemisphere, and can also detect the African-lineage Zika virus strain using separate, specific primers. PMID:28469032

Assessment of Chemical and Physico-Chemical Properties of Cyanobacterial Lipids for Biodiesel Production

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Heizir F. De Castro

2013-07-01

Full Text Available Five non-toxin producing cyanobacterial isolates from the genera Synechococcus, Trichormus, Microcystis, Leptolyngbya and Chlorogloea were examined in terms of quantity and quality as lipid feedstock for biofuel production. Under the conditions used in this study, the biomass productivity ranged from 3.7 to 52.7 mg·L−1·day−1 in relation to dry biomass, while the lipid productivity varied between 0.8 and 14.2 mg·L−1·day−1. All cyanobacterial strains evaluated yielded lipids with similar fatty acid composition to those present in the seed oils successfully used for biodiesel synthesis. However, by combining biomass and lipid productivity parameters, the greatest potential was found for Synechococcus sp. PCC7942, M. aeruginosa NPCD-1 and Trichormus sp. CENA77. The chosen lipid samples were further characterized using Fourier Transform Infrared spectroscopy (FTIR, viscosity and thermogravimetry and used as lipid feedstock for biodiesel synthesis by heterogeneous catalysis.

A curated database of cyanobacterial strains relevant for modern taxonomy and phylogenetic studies.

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Ramos, Vitor; Morais, João; Vasconcelos, Vitor M

2017-04-25

The dataset herein described lays the groundwork for an online database of relevant cyanobacterial strains, named CyanoType (http://lege.ciimar.up.pt/cyanotype). It is a database that includes categorized cyanobacterial strains useful for taxonomic, phylogenetic or genomic purposes, with associated information obtained by means of a literature-based curation. The dataset lists 371 strains and represents the first version of the database (CyanoType v.1). Information for each strain includes strain synonymy and/or co-identity, strain categorization, habitat, accession numbers for molecular data, taxonomy and nomenclature notes according to three different classification schemes, hierarchical automatic classification, phylogenetic placement according to a selection of relevant studies (including this), and important bibliographic references. The database will be updated periodically, namely by adding new strains meeting the criteria for inclusion and by revising and adding up-to-date metadata for strains already listed. A global 16S rDNA-based phylogeny is provided in order to assist users when choosing the appropriate strains for their studies.

A population of human brain cells expressing phenotypic markers of more than one lineage can be induced in vitro to differentiate into mesenchymal cells

International Nuclear Information System (INIS)

Rieske, Piotr; Augelli, Brian J.; Stawski, Robert; Gaughan, John; Azizi, S. Ausim; Krynska, Barbara

2009-01-01

Proliferating astrocytic cells from germinal, as well as mature areas of brain parenchyma, have the characteristics of neural stem/progenitor cells and are capable of generating both neurons and glia. We previously reported that primary fetal human brain cells, designated as Normal Human Astrocytes (NHA), expressed, in addition to GFAP, Vimentin and Nestin, low levels of βIII-Tubulin, an early neuronal marker, and differentiated into neurons and astrocytes in vitro. Here, we showed that primary NHA cells co-express low levels of mesenchymal markers Fibronectin and Collagen-1 in culture. These cells transitioned into mesenchymal-like cells when cultured in adherent conditions in serum containing media. The mesenchymal-like derivatives of these cells were characterized based on their morphological changes, high expression of Vimentin and extracellular matrix (ECM) proteins, Collagen-1 and Fibronectin, and decline of neural markers. When incubated in osteogenic and adipogenic induction media, the mesenchymal-like cells differentiated into osteoblasts and adipocytes. Furthermore, NHA cells express markers of neural crest cells, SOX-10 and p75. These data support the idea of ectoderm-derived mesenchymal lineages. These findings suggest that a population of primitive fetal brain cells with neural/neural crest/mesenchymal phenotype, resembles the remarkable phenotypic plasticity of neural crest cells, and differentiates into adipocytes and osteocytes under the influence of environmental factors

Cyanobacterial Diversity in Microbial Mats from the Hypersaline Lagoon System of Araruama, Brazil: An In-depth Polyphasic Study

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Vitor M. C. Ramos

2017-06-01

Full Text Available Microbial mats are complex, micro-scale ecosystems that can be found in a wide range of environments. In the top layer of photosynthetic mats from hypersaline environments, a large diversity of cyanobacteria typically predominates. With the aim of strengthening the knowledge on the cyanobacterial diversity present in the coastal lagoon system of Araruama (state of Rio de Janeiro, Brazil, we have characterized three mat samples by means of a polyphasic approach. We have used morphological and molecular data obtained by culture-dependent and -independent methods. Moreover, we have compared different classification methodologies and discussed the outcomes, challenges, and pitfalls of these methods. Overall, we show that Araruama's lagoons harbor a high cyanobacterial diversity. Thirty-six unique morphospecies could be differentiated, which increases by more than 15% the number of morphospecies and genera already reported for the entire Araruama system. Morphology-based data were compared with the 16S rRNA gene phylogeny derived from isolate sequences and environmental sequences obtained by PCR-DGGE and pyrosequencing. Most of the 48 phylotypes could be associated with the observed morphospecies at the order level. More than one third of the sequences demonstrated to be closely affiliated (best BLAST hit results of ≥99% with cyanobacteria from ecologically similar habitats. Some sequences had no close relatives in the public databases, including one from an isolate, being placed as “loner” sequences within different orders. This hints at hidden cyanobacterial diversity in the mats of the Araruama system, while reinforcing the relevance of using complementary approaches to study cyanobacterial diversity.

Cyanobacterial Diversity in Microbial Mats from the Hypersaline Lagoon System of Araruama, Brazil: An In-depth Polyphasic Study.

Science.gov (United States)

Ramos, Vitor M C; Castelo-Branco, Raquel; Leão, Pedro N; Martins, Joana; Carvalhal-Gomes, Sinda; Sobrinho da Silva, Frederico; Mendonça Filho, João G; Vasconcelos, Vitor M

2017-01-01

Microbial mats are complex, micro-scale ecosystems that can be found in a wide range of environments. In the top layer of photosynthetic mats from hypersaline environments, a large diversity of cyanobacteria typically predominates. With the aim of strengthening the knowledge on the cyanobacterial diversity present in the coastal lagoon system of Araruama (state of Rio de Janeiro, Brazil), we have characterized three mat samples by means of a polyphasic approach. We have used morphological and molecular data obtained by culture-dependent and -independent methods. Moreover, we have compared different classification methodologies and discussed the outcomes, challenges, and pitfalls of these methods. Overall, we show that Araruama's lagoons harbor a high cyanobacterial diversity. Thirty-six unique morphospecies could be differentiated, which increases by more than 15% the number of morphospecies and genera already reported for the entire Araruama system. Morphology-based data were compared with the 16S rRNA gene phylogeny derived from isolate sequences and environmental sequences obtained by PCR-DGGE and pyrosequencing. Most of the 48 phylotypes could be associated with the observed morphospecies at the order level. More than one third of the sequences demonstrated to be closely affiliated (best BLAST hit results of ≥99%) with cyanobacteria from ecologically similar habitats. Some sequences had no close relatives in the public databases, including one from an isolate, being placed as "loner" sequences within different orders. This hints at hidden cyanobacterial diversity in the mats of the Araruama system, while reinforcing the relevance of using complementary approaches to study cyanobacterial diversity.

Rapid reactivation of cyanobacterial photosynthesis and migration upon rehydration of desiccated marine microbial mats

NARCIS (Netherlands)

Chennu, Arjun; Grinham, Alistair; Polerecky, Lubos; de Beer, Dirk; Al-Najjar, Mohammad A.A.

2015-01-01

Desiccated cyanobacterial mats are the dominant biological feature in the Earth's arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution

Hypoxia-induced pulmonary vascular remodeling requires recruitment of circulating mesenchymal precursors of a monocyte/macrophage lineage.

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Frid, Maria G; Brunetti, Jacqueline A; Burke, Danielle L; Carpenter, Todd C; Davie, Neil J; Reeves, John T; Roedersheimer, Mark T; van Rooijen, Nico; Stenmark, Kurt R

2006-02-01

Vascular remodeling in chronic hypoxic pulmonary hypertension includes marked fibroproliferative changes in the pulmonary artery (PA) adventitia. Although resident PA fibroblasts have long been considered the primary contributors to these processes, we tested the hypothesis that hypoxia-induced pulmonary vascular remodeling requires recruitment of circulating mesenchymal precursors of a monocyte/macrophage lineage, termed fibrocytes. Using two neonatal animal models (rats and calves) of chronic hypoxic pulmonary hypertension, we demonstrated a dramatic perivascular accumulation of mononuclear cells of a monocyte/macrophage lineage (expressing CD45, CD11b, CD14, CD68, ED1, ED2). Many of these cells produced type I collagen, expressed alpha-smooth muscle actin, and proliferated, thus exhibiting mesenchymal cell characteristics attributed to fibrocytes. The blood-borne origin of these cells was confirmed in experiments wherein circulating monocytes/macrophages of chronically hypoxic rats were in vivo-labeled with DiI fluorochrome via liposome delivery and subsequently identified in the remodeled pulmonary, but not systemic, arterial adventitia. The DiI-labeled cells that appeared in the vessel wall expressed monocyte/macrophage markers and procollagen. Selective depletion of this monocytic cell population, using either clodronate-liposomes or gadolinium chloride, prevented pulmonary adventitial remodeling (ie, production of collagen, fibronectin, and tenascin-C and accumulation of myofibroblasts). We conclude that circulating mesenchymal precursors of a monocyte/macrophage lineage, including fibrocytes, are essential contributors to hypoxia-induced pulmonary vascular remodeling.

The influence of TSA and VPA on the in vitro differentiation of bone marrow mesenchymal stem cells into neuronal lineage cells: Gene expression studies.

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Fila-Danilow, Anna; Borkowska, Paulina; Paul-Samojedny, Monika; Kowalczyk, Malgorzata; Kowalski, Jan

2017-03-27

Epigenetic mechanisms regulate the transcription of genes, which can affect the differentiation of MSCs. The aim of the current work is to determine how the histone deacetylase inhibitors TSA and VPA affect the expression of neuronal lineage genes in a culture of rat MSCs (rMSCs). We analyzed the expression of early neuron marker gene (Tubb3), mature neuron markers genes (Vacht, Th, Htr2a) and the oligodendrocyte progenitor marker gene (GalC). Moreover, changes in the gene expression after three different periods of exposure to TSA and VPA were investigated for the first time. After six days of exposition to TSA and VPA, the expression of Tubb3 and GalC decreased, while the expression of Th increased. The highest increase of VAChT expression was observed after three days of TSA and VPA treatment. A decrease in Htr2a gene expression was observed after TSA treatment and an increase was observed after VPA treatment. We also observed that TSA and VPA inhibited cell proliferation and the formation of neurospheres in the rMSCs culture. The central findings of our study are that TSA and VPA affect the expression of neuronal lineage genes in an rMSCs culture. After exposure to TSA or VPA, the expression of early neuronal gene decreases but equally the expression of mature neuron genes increases. After TSA and VPA treatment ER of the oligodendrocyte progenitor marker decreased. TSA and VPA inhibit cell proliferation and the formation of neurospheres in rMSCs culture.

Single-Cell RNA-Sequencing Reveals a Continuous Spectrum of Differentiation in Hematopoietic Cells

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Iain C. Macaulay

2016-02-01

Full Text Available The transcriptional programs that govern hematopoiesis have been investigated primarily by population-level analysis of hematopoietic stem and progenitor cells, which cannot reveal the continuous nature of the differentiation process. Here we applied single-cell RNA-sequencing to a population of hematopoietic cells in zebrafish as they undergo thrombocyte lineage commitment. By reconstructing their developmental chronology computationally, we were able to place each cell along a continuum from stem cell to mature cell, refining the traditional lineage tree. The progression of cells along this continuum is characterized by a highly coordinated transcriptional program, displaying simultaneous suppression of genes involved in cell proliferation and ribosomal biogenesis as the expression of lineage specific genes increases. Within this program, there is substantial heterogeneity in the expression of the key lineage regulators. Overall, the total number of genes expressed, as well as the total mRNA content of the cell, decreases as the cells undergo lineage commitment.

Mixed lineage kinase 3 is required for matrix metalloproteinase expression and invasion in ovarian cancer cells

International Nuclear Information System (INIS)

Zhan, Yu; Abi Saab, Widian F.; Modi, Nidhi; Stewart, Amanda M.; Liu, Jinsong; Chadee, Deborah N.

2012-01-01

Mixed lineage kinase 3 (MLK3) is a mitogen-activated protein kinase kinase kinase (MAP3K) that activates MAPK signaling pathways and regulates cellular responses such as proliferation, migration and apoptosis. Here we report high levels of total and phospho-MLK3 in ovarian cancer cell lines in comparison to immortalized nontumorigenic ovarian epithelial cell lines. Using small interfering RNA (siRNA)-mediated gene silencing, we determined that MLK3 is required for the invasion of SKOV3 and HEY1B ovarian cancer cells. Furthermore, mlk3 silencing substantially reduced matrix metalloproteinase (MMP)-1, -2, -9 and -12 gene expression and MMP-2 and -9 activities in SKOV3 and HEY1B ovarian cancer cells. MMP-1, -2, -9 and-12 expression, and MLK3-induced activation of MMP-2 and MMP-9 requires both extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activities. In addition, inhibition of activator protein-1 (AP-1) reduced MMP-1, MMP-9 and MMP-12 gene expression. Collectively, these findings establish MLK3 as an important regulator of MMP expression and invasion in ovarian cancer cells. -- Highlights: ► Ovarian cancer cell lines have high levels of total and phosphorylated MLK3. ► MLK3 is required for MMP expression and activity in ovarian cancer cells. ► MLK3 is required for invasion of SKOV3 and HEY1B ovarian cancer cells. ► MLK3-dependent regulation of MMP-2 and MMP-9 activities requires ERK and JNK.

Affinity maturation in an HIV broadly neutralizing B-cell lineage through reorientation of variable domains.

Science.gov (United States)

Fera, Daniela; Schmidt, Aaron G; Haynes, Barton F; Gao, Feng; Liao, Hua-Xin; Kepler, Thomas B; Harrison, Stephen C

2014-07-15

Rapidly evolving pathogens, such as human immunodeficiency and influenza viruses, escape immune defenses provided by most vaccine-induced antibodies. Proposed strategies to elicit broadly neutralizing antibodies require a deeper understanding of antibody affinity maturation and evolution of the immune response to vaccination or infection. In HIV-infected individuals, viruses and B cells evolve together, creating a virus-antibody "arms race." Analysis of samples from an individual designated CH505 has illustrated the interplay between an antibody lineage, CH103, and autologous viruses at various time points. The CH103 antibodies, relatively broad in their neutralization spectrum, interact with the CD4 binding site of gp120, with a contact dominated by CDRH3. We show by analyzing structures of progenitor and intermediate antibodies and by correlating them with measurements of binding to various gp120s that there was a shift in the relative orientation of the light- and heavy-chain variable domains during evolution of the CH103 lineage. We further show that mutations leading to this conformational shift probably occurred in response to insertions in variable loop 5 (V5) of the HIV envelope. The shift displaced the tips of the light chain away from contact with V5, making room for the inserted residues, which had allowed escape from neutralization by the progenitor antibody. These results, which document the selective mechanism underlying this example of a virus-antibody arms race, illustrate the functional significance of affinity maturation by mutation outside the complementarity determining region surface of the antibody molecule.

Lineage specific recombination rates and microevolution in Listeria monocytogenes

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Nightingale Kendra K

2008-10-01

Full Text Available Abstract Background The bacterium Listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages I and II and an uncommon lineage (lineage III. While some L. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to L. monocytogenes evolution is still limited. We therefore used STRUCTURE and ClonalFrame, two programs that model the effect of recombination, to make inferences about the population structure and different aspects of the recombination process in L. monocytogenes. Analyses were performed using sequences for seven loci (including the house-keeping genes gap, prs, purM and ribC, the stress response gene sigB, and the virulence genes actA and inlA for 195 L. monocytogenes isolates. Results Sequence analyses with ClonalFrame and the Sawyer's test showed that recombination is more prevalent in lineage II than lineage I and is most frequent in two house-keeping genes (ribC and purM and the two virulence genes (actA and inlA. The relative occurrence of recombination versus point mutation is about six times higher in lineage II than in lineage I, which causes a higher genetic variability in lineage II. Unlike lineage I, lineage II represents a genetically heterogeneous population with a relatively high proportion (30% average of genetic material imported from external sources. Phylograms, constructed with correcting for recombination, as well as Tajima's D data suggest that both lineages I and II have suffered a population bottleneck. Conclusion Our study shows that evolutionary lineages within a single bacterial species can differ considerably in the relative contributions of recombination to genetic diversification. Accounting for recombination in phylogenetic studies is critical, and new evolutionary models that