scholarly journals Co-culture and biogeography of Prochlorococcus and SAR11

2018 ◽  
Author(s):  
Jamie W. Becker ◽  
Shane L. Hogle ◽  
Kali Rosendo ◽  
Sallie W. Chisholm
Keyword(s):  
Organic Carbon ◽  
Glycine Betaine ◽  
Euphotic Zone ◽  
Nutrient Requirements ◽  
Low Light ◽  
Relative Contribution ◽  
Ocean Gyres ◽  
Global Population ◽  
Copiotrophic Bacteria

AbstractProchlorococcus and SAR11 are among the smallest and most abundant organisms on Earth. With a combined global population of about 2.7 x 1028 cells, they numerically dominate bacterioplankton communities in oligotrophic ocean gyres and yet they have never been grown together in vitro. Here we describe co-cultures of Prochlorococcus and SAR11 isolates representing both high- and low-light adapted clades. We examined: (1) the influence of Prochlorococcus on the growth of SAR11 and vice-versa, (2) whether Prochlorococcus can meet specific nutrient requirements of SAR11, and (3) how co-culture dynamics vary when Prochlorococcus is grown with SAR11 compared with sympatric copiotrophic bacteria. SAR11 grew as much as 70% faster in the presence of Prochlorococcus, while the growth of the latter was unaffected. When Prochlorococcus populations entered stationary phase, SAR11 abundances decreased dramatically. In parallel experiments with copiotrophic bacteria however, the heterotrophic partner increased in abundance as Prochlorococcus densities leveled off. The presence of Prochlorococcus was able to meet SAR11’s central requirement for organic carbon, but not reduced sulfur. Prochlorococcus strain MIT9313, but not MED4, could meet the unique glycine requirement of SAR11, likely due to production and release of glycine betaine by MIT9313. Evidence suggests that Prochlorococcus MIT9313 may also compete with SAR11 for the uptake of 3-dimethylsulfoniopropionate (DMSP). To place our results in context, we assessed the relative contribution of Prochlorococcus and SAR11 genome equivalents to those of identifiable bacteria and archaea in over 800 marine metagenomes. At many locations, more than half of the identifiable genome equivalents in the euphotic zone belonged to Prochlorococcus and SAR11 – highlighting the biogeochemical potential of these two groups.

scholarly journals Reduced Ex Vivo Interleukin-8 Production by Neutrophils in Septic and Nonseptic Systemic Inflammatory Response Syndrome

Blood ◽  
1998 ◽  
Vol 91 (9) ◽  
pp. 3439-3446 ◽  
Author(s):  
Christelle Marie ◽  
Jane Muret ◽  
Catherine Fitting ◽  
Marie-Reine Losser ◽  
Didier Payen ◽  
...  
Keyword(s):  
Systemic Inflammatory Response Syndrome ◽  
Inflammatory Response ◽  
Ex Vivo ◽  
Endotoxin Tolerance ◽  
Systemic Inflammatory Response ◽  
Interleukin 8 ◽  
Polymorphonuclear Cells ◽  
Healthy Controls ◽  
Relative Contribution

AbstractEx vivo cytokine production by circulating lymphocytes and monocytes is reduced in patients with infectious or noninfectious systemic inflammatory response syndrome. Very few studies have addressed the reactivity of polymorphonuclear cells (PMN). To analyze further the relative contribution of systemic inflammatory response syndrome alone or in combination with infection we studied the interleukin-8 (IL-8) production by PMN isolated from patients who had undergone cardiac surgery with cardiopulmonary bypass (CPB) and patients with sepsis. Cells were activated with either lipopolysaccharide (LPS) or heat-killed streptococci. Compared with healthy controls, the release of IL-8 by PMN in both groups of patients was significantly reduced whether activated by LPS, independently of its concentration and origin, or by heat-killed streptococci. These observations suggest that stressful conditions related to inflammation, independently of infection, rapidly dampened the reactivity of circulating PMN. We investigated whether the observed diminished reactivity of PMN might reflect an endotoxin tolerance phenomenon. Our in vitro experiments with PMN from healthy controls indicated that PMN could not be rendered tolerant stricto sensu. However, our data suggested that LPS-induced mediators such as IL-10 may be responsible for the observed anergy in patients.

Photoinhibition of DCMU-Enhanced Fluorescence in Lake Ontario Phytoplankton

1987 ◽  
Vol 44 (12) ◽  
pp. 2144-2154 ◽  
Author(s):  
M. Putt ◽  
G. P. Harris ◽  
R. L. Cuhel
Keyword(s):  
Vertical Mixing ◽  
Natural Populations ◽  
Bright Light ◽  
Euphotic Zone ◽  
Lake Ontario ◽  
Enhanced Fluorescence ◽  
Low Light ◽  
Light Levels ◽  
Phosphorus Status

Measurement of 1-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) enhanced fluorescence (FDCMU) suggested that photoinhibition of photosynthesis was frequently an artifact of in situ bottle incubations in Lake Ontario phytoplankton. In a seasonal study, FDCMU of all populations was depressed by bright light in an incubator. However, when the euphotic zone did not exceed the depth of the mixed layer, vertical transport of phytoplankton into either low-light or dark regions apparently allowed reversal of photoinhibition of FDCMU. Advantages of FDCMU as a bioassay of vertical mixing include rapidity of response time, ease of measurement in the field, and insensitivity of this parameter to changes in phosphorus status of the population. Because of seasonal changes in the photoadaptive response of natural populations, the rate constants and threshold light levels required to cause the response must be determined at each use if the method is to be quantitative.

Cyclooxygenase-2 plays a significant role in regulating the tone of the fetal lamb ductus arteriosus

1999 ◽  
Vol 276 (3) ◽  
pp. R913-R921 ◽  
Author(s):  
Ronald I. Clyman ◽  
Pierre Hardy ◽  
Nahid Waleh ◽  
Yao Qi Chen ◽  
Françoise Mauray ◽  
...  
Keyword(s):  
Significant Role ◽  
Ductus Arteriosus ◽  
Late Gestation ◽  
Relative Contribution ◽  
Cox Inhibitor ◽  
Fetal Lamb ◽  
Cox 2 ◽  
Cox 2 Inhibitors ◽  
Cox 1

Nonselective cyclooxygenase (COX) inhibitors are potent tocolytic agents but have adverse effects on the fetal ductus arteriosus. We hypothesized that COX-2 inhibitors may not affect the ductus if the predominant COX isoform is COX-1. To examine this hypothesis, we used ductus arteriosus obtained from late-gestation fetal lambs. In contrast to our hypothesis, fetal lamb ductus arteriosus expressed both COX-1- and COX-2-immunoreactive protein (by Western analysis). Although COX-1 was found in both endothelial and smooth muscle cells, COX-2 was found only in the endothelial cells lining the ductus lumen (by immunohistochemistry). The relative contribution of COX-1 and COX-2 to PGE2 synthesis was consistent with the immunohistochemical results: in the intact ductus, PGE2 formation was catalyzed by both COX-1 and COX-2 in equivalent proportions; in the endothelium-denuded ductus, COX-2 no longer played a significant role in PGE2 synthesis. NS-398, a selective inhibitor of COX-2, was 66% as effective as the selective COX-1 inhibitor valeryl salicylate and the nonselective COX inhibitor indomethacin in causing contraction of the ductus in vitro. At this time, caution should be used when recommending COX-2 inhibitors for use in pregnant women.

Alterations in diaphragm contractility after nandrolone administration: an analysis of potential mechanisms

1999 ◽  
Vol 86 (3) ◽  
pp. 985-992 ◽  
Author(s):  
Michael I. Lewis ◽  
Mario Fournier ◽  
Amelia Y. Yeh ◽  
Paul E. Micevych ◽  
Gary C. Sieck
Keyword(s):  
Atpase Activity ◽  
Maximum Velocity ◽  
Interstitial Space ◽  
Myosin Atpase ◽  
Fiber Types ◽  
Intact Male ◽  
Cross Sectional ◽  
Myosin Atpase Activity ◽  
Relative Contribution

The aim of this study was to evaluate the potential mechanisms underlying the improved contractility of the diaphragm (Dia) in adult intact male hamsters after nandrolone (Nan) administration, given subcutaneously over 4 wk via a controlled-release capsule (initial dose: 4.5 mg ⋅ kg−1 ⋅ day−1; with weight gain, final dose: 2.7 mg ⋅ kg−1 ⋅ day−1). Control (Ctl) animals received blank capsules. Isometric contractile properties of the Dia were determined in vitro after 4 wk. The maximum velocity of unloaded shortening ( V o) was determined in vitro by means of the slack test. Dia fibers were classified histochemically on the basis of myofibrillar ATPase staining and fiber cross-sectional area (CSA), and the relative interstitial space was quantitated. Ca2+-activated myosin ATPase activity was determined by quantitative histochemistry in individual diaphragm fibers. Myosin heavy chain (MHC) isoforms were identified electrophoretically, and their proportions were determined by using scanning densitometry. Peak twitch and tetanic forces, as well as V o, were significantly greater in Nan animals compared with Ctl. The proportion of type IIa Dia fibers was significantly increased in Nan animals. Nan increased the CSA of all fiber types (26–47%), whereas the relative interstitial space decreased. The relative contribution of fiber types to total costal Dia area was preserved between the groups. Proportions of MHC isoforms were similar between the groups. There was a tendency for increased expression of MHC2B with Nan. Ca2+-activated myosin ATPase activity was increased 35–39% in all fiber types in Nan animals. We conclude that, after Nan administration, the increase in Dia specific force results from the relatively greater Dia CSA occupied by hypertrophied muscle fibers, whereas the increased ATPase activity promotes a higher rate of cross-bridge turnover and thus increased V o. We speculate that Nan in supraphysiological doses have the potential to offset or ameliorate conditions associated with enhanced proteolysis and disordered protein turnover.

Relative Contribution of CYP3A to Amitriptyline Clearance in Humans: In Vitro and In Vivo Studies

2001 ◽  
Vol 41 (10) ◽  
pp. 1043-1054 ◽  
Author(s):  
Karthik Venkatakrishnan ◽  
Jürgen Schmider ◽  
Jerold S. Harmatz ◽  
Bruce L. Ehrenberg ◽  
Lisa L. von Moltke ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Relative Contribution

Differential activation of ER stress and apoptosis in response to chronically elevated free fatty acids in pancreatic β-cells

2008 ◽  
Vol 294 (3) ◽  
pp. E540-E550 ◽  
Author(s):  
Elida Lai ◽  
George Bikopoulos ◽  
Michael B. Wheeler ◽  
Maria Rozakis-Adcock ◽  
Allen Volchuk
Keyword(s):  
Er Stress ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Human Islets ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Min6 Cells ◽  
Relative Contribution ◽  
Induced Apoptosis

Chronic exposure to elevated saturated free fatty acid (FFA) levels has been shown to induce endoplasmic reticulum (ER) stress that may contribute to promoting pancreatic β-cell apoptosis. Here, we compared the effects of FFAs on apoptosis and ER stress in human islets and two pancreatic β-cell lines, rat INS-1 and mouse MIN6 cells. Isolated human islets cultured in vitro underwent apoptosis, and markers of ER stress pathways were elevated by chronic palmitate exposure. Palmitate also induced apoptosis in MIN6 and INS-1 cells, although the former were more resistant to both apoptosis and ER stress. MIN6 cells were found to express significantly higher levels of ER chaperone proteins than INS-1 cells, which likely accounts for the ER stress resistance. We attempted to determine the relative contribution that ER stress plays in palmitate-induced β-cell apoptosis. Although overexpressing GRP78 in INS-1 cells partially reduced susceptibility to thapsigargin, this failed to reduce palmitate-induced ER stress or apoptosis. In INS-1 cells, palmitate induced apoptosis at concentrations that did not result in significant ER stress. Finally, MIN6 cells depleted of GRP78 were more susceptible to tunicamycin-induced apoptosis but not to palmitate-induced apoptosis compared with control cells. These results suggest that ER stress is likely not the main mechanism involved in palmitate-induced apoptosis in β-cell lines. Human islets and MIN6 cells were found to express high levels of stearoyl-CoA desaturase-1 compared with INS-1 cells, which may account for the decreased susceptibility of these cells to the cytotoxic effects of palmitate.

scholarly journals Impact of Glycine Betaine on Salinity Tolerance of Stevia (Stevia rebaudiana Bertoni) under In Vitro Condition

2017 ◽  
Vol 50 (3) ◽  
pp. 95-105 ◽  
Author(s):  
V. Rameeh ◽  
M. Gerami ◽  
V. Ghasemi Omran ◽  
S. Ghavampour
Keyword(s):  
Glycine Betaine ◽  
Stevia Rebaudiana ◽  
Mean Value ◽  
Rebaudioside A ◽  
Stevia Rebaudiana Bertoni ◽  
Nacl Concentration ◽  
Salinity Levels ◽  
High Concentrations

Abstract Stevia (Stevia rebaudiana Bertoni), with great potential as a natural sweeteners source, has a high content of sweeteners, which are up to 150 times sweeter than sugar, but virtually with no calories. Stevia also suitable to be cultivated in semiarid climates and coastal areas, which are characterized by the low quality of the irrigation water. Soil salinity occupies a prominent place among the soil problems that threaten the sustainability of agriculture over a vast area in the world. Glycine betaine is an osmoprotectant, that plays an important role and accumulates rapidly in many plants during salinity or drought stress. In order to evaluation of glycine betaine amending effects on salinity stress in stevia under in vitro condition, a factorial experiment was conducted in 2015. Four NaCl levels, including 0, 50, 75 and 100 mM, along with 0, 1, 12.5, 25 and 50 mM of glycine betaine concentrations were used in Murashige and Skoog (MS) medium. The results showed that salinity levels had significant reduction effects on plant height, root length, shoot fresh weight, number of leaf, total chlorophyll, rebaudioside A and stevioside of the stevia genotype. Due to increasing of glycine betaine, levels all the traits were increased. Owing to amending effect of glycine betaine, its high concentrations made less hazarding effects of salinity on the researched traits. The highest mean value of rebaudioside A (10.62rt) and stevioside (23.38rt) determined at 50 mM of glycine betaine with 0 mM of NaCl concentration.

scholarly journals Reduced Ex Vivo Interleukin-8 Production by Neutrophils in Septic and Nonseptic Systemic Inflammatory Response Syndrome

Blood ◽  
1998 ◽  
Vol 91 (9) ◽  
pp. 3439-3446 ◽  
Author(s):  
Christelle Marie ◽  
Jane Muret ◽  
Catherine Fitting ◽  
Marie-Reine Losser ◽  
Didier Payen ◽  
...  
Keyword(s):  
Systemic Inflammatory Response Syndrome ◽  
Inflammatory Response ◽  
Ex Vivo ◽  
Endotoxin Tolerance ◽  
Systemic Inflammatory Response ◽  
Interleukin 8 ◽  
Polymorphonuclear Cells ◽  
Healthy Controls ◽  
Relative Contribution

Ex vivo cytokine production by circulating lymphocytes and monocytes is reduced in patients with infectious or noninfectious systemic inflammatory response syndrome. Very few studies have addressed the reactivity of polymorphonuclear cells (PMN). To analyze further the relative contribution of systemic inflammatory response syndrome alone or in combination with infection we studied the interleukin-8 (IL-8) production by PMN isolated from patients who had undergone cardiac surgery with cardiopulmonary bypass (CPB) and patients with sepsis. Cells were activated with either lipopolysaccharide (LPS) or heat-killed streptococci. Compared with healthy controls, the release of IL-8 by PMN in both groups of patients was significantly reduced whether activated by LPS, independently of its concentration and origin, or by heat-killed streptococci. These observations suggest that stressful conditions related to inflammation, independently of infection, rapidly dampened the reactivity of circulating PMN. We investigated whether the observed diminished reactivity of PMN might reflect an endotoxin tolerance phenomenon. Our in vitro experiments with PMN from healthy controls indicated that PMN could not be rendered tolerant stricto sensu. However, our data suggested that LPS-induced mediators such as IL-10 may be responsible for the observed anergy in patients.

scholarly journals In Situ Estimation of Carbon Balance of In Vitro Sweetpotato and Tomato Plantlets Cultured with Varying Initial Sucrose Concentrations in the Medium

2002 ◽  
Vol 127 (6) ◽  
pp. 963-970 ◽  
Author(s):  
Chieri Kubota ◽  
Makiko Ezawa ◽  
Toyoki Kozai ◽  
Sandra B. Wilson
Keyword(s):  
Carbon Balance ◽  
Ipomoea Batatas ◽  
Dry Weight ◽  
Photon Flux ◽  
Sugar Uptake ◽  
Relative Contribution ◽  
Carbon Balances ◽  
Species Specific

The effects of initial sucrose (suc) concentrations in the medium (S0) on the carbon balance and growth of sweetpotato [Ipomoea batatas (L.) Lam. `Beniazuma'] and tomato (Lycopersicon esculentum Mill. `HanaQueen') plantlets were studied under controlled environmental conditions. Plantlets were cultured with 0, 7.5, 15, or 30 g·L-1 of S0 under high photosynthetic photon flux (160 to 200 μmol·m-2·s-1) and CO2 enriched (1400 to 2050 μmol·mol-1) conditions. Net photosynthetic rate per leaf area (Pl) decreased and dry weight per plantlet (Wd) increased with increasing S0, but did not differ significantly between S0 of 7.5 to 30 g·L-1 for sweetpotato or 15 to 30 g·L-1 for tomato. Carbon influxes and effluxes of the plantlets by metabolism of medium suc and/or photosynthesis, and respiration were estimated based on measurements of in situ and steady state CO2 exchange rates and sugar uptake during culture. At S0 from 7.5 to 30 g·L-1, photosynthesis was responsible for 82% to 92% and 60% to 67% of carbohydrate assimilation for sweetpotato and tomato, respectively. Estimated carbon balances of plantlets based on the estimated and actual increases of moles of carbon in plant tissue demonstrated that in situ estimation of carbon balance was reasonably accurate for sweetpotato at S0 of 0 to 15 g·L-1 and for tomato at S0 of 0 g·L-1 and that the actual contribution of photosynthesis for tomato at high S0 might be lower than the values estimated in the present experiment. Results showed that initial suc concentration affected the relative contribution of photosynthesis on their carbon balances and that the responses were species specific. The failure of validation at S0 in a range specific to each species suggested the need for further study on carbon metabolism of in vitro plantlets cultured with sugar in the medium.

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