The intestine is composed of many distinct cell types that respond to commensal microbiota or pathogens with immune tolerance and proinflammatory signals respectively. ROS produced by mucosa‐resident ...cells or by newly recruited innate immune cells are essential for antimicrobial responses and regulation of signalling pathways including processes involved in wound healing. Impaired ROS production due to inactivating patient variants in genes encoding NADPH oxidases as ROS source has been associated with Crohn's disease and pancolitis, whereas overproduction of ROS due to up‐regulation of oxidases or altered mitochondrial function was linked to ileitis and ulcerative colitis. Here, we discuss recent advances in our understanding of how maintaining a redox balance is crucial to preserve gut homeostasis.
Linked Articles
This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc
Two identical coupled warmwater ebb-and-flood gravel aquaponic systems (unit I, unit II) without additional biofilter were evaluated for the effect of fish species choice onto culinary herbs (basil - ...Ocimum basilicum, parsley - Petroselinum crispum and marjoram - Origanum majorana) and resulting water parameters. The daily feed input increased over the experiment (70–450g, total 70days), resulting in an maximum feed input of 150gd−1, or 25% less than during an earlier study under the presence of a 60L trickling biofilter. Using dissolved oxygen to indicate system performance, the experiment had a run in phase, exponential phase, and accumulation phase. Lowest dissolved oxygen (DO) concentrations were measured inside the hydroponic units, with no general differences in chemo-physical parameters between each separate plant box. Nile tilapia red strain fingerlings (Oreochromis niloticus; initial weight 3.32g±1.63) were stocked in aquaponic unit I and African catfish fingerlings (Clarias gariepinus; initial weight 3.92g±1.63) in unit II. Due to the high feed input at the beginning of the experiments, specific growth rate and feed conversion ratio were very good, and significantly better for C. gariepinus (3.30%d−1±0.02, 0.61±0.01) compared with O. niloticus (2.81%d−1±0.12, 0.91±0.08). Feed conversion corresponded with much younger fish with effective feeding under restricted food input. The oxygen consumption was lower for C. gariepinus with a difference of 8.34% to O. niloticus. Due to reduced natural light illumination and water temperature (winter season), plant growth was generally reduced but two times better in the O. niloticus stocked unit (0.30g±0.37 in basil, 0.55g±0.39 in parsley) compared with C. gariepinus (0.12g±0.21 in basil, 0.27g±0.31 in parsley). A newly calculated aquaponic growth factor (AGF) illustrates the opposite fish and plant yields for both fish species.
Statement of relevance: The influence of different fish species on plant growth has been examined only rarely in aquaponics. We hereby describe the influence of different types of fish on physical parameters and plant growth in coupled aquaponic systems for diversification.
•Fish biology is influencing yield of aquaponically cultured basil (Ocimum basilicum), parsley (Petroselinum crispum) and marjoram (Origanum majorana) with better harvest in combination with Nile tilapia (Oreochromis niloticus).•Weight gain of African catfish (Clarias gariepinus) was better in comparison with Nile tilapia (Oreochromis niloticus).•Steadily increasing feed input per day resulted in a three phase water oxygen distribution (run in phase, exponential phase, and accumulation phase) in a coupled aquaponic system with a steady state at 150 g feed input per day.
P21-activated kinases (Paks), a family of serine/threonine kinases, are effectors of the Rho GTPases Cdc42 and Rac1. Mammalian Pak1 and Pak homologs in simple eukaryotes are implicated in controlling ...G(2)/M transition and/or mitosis. Another serine/threonine kinase, polo-like kinase 1 (Plk1), is an important regulator of mitotic events, such as centrosome maturation, mitotic entry, spindle formation, sister chromatid cohesion and cytokinesis. Plk1 phosphorylation is thought to be one of the critical regulatory events leading to these Plk1-mediated functions. We show here that Pak1 is required for cell proliferation, mitotic progression and Plk1 activity in HeLa cells. Gain or loss of Pak function directly impacted phosphorylation and activity of Plk1. Phosphorylation of Plk1 on Ser 49 is important for metaphase-associated events. Inhibition of Pak activity leads to delay in G(2)/M progression and abnormal spindle formation, mirroring some attributes of Plk1 deregulation. Our results reveal a role for Pak in regulating Plk1 activity and mitotic progression, and connect Pak to the complex protein interaction network enabling cell division.
Rac1 is a member of the Ras superfamily of small guanosine triphosphatases (GTPases) that act as molecular switches to control cytoskeletal rearrangements and cell growth. Analogous to Ras, ...constitutively activating point mutations of Rac1 cause tumorigenic transformation of cell lines. However, there is no information about whether Rac1 is also mutated in vivo. After RT - PCR of Rac1, several clones of seven benign and 10 malignant breast cancer tissues as well as eight breast cancer cell lines were sequenced. Only single-nucleotide polymorphisms of Rac1 could be detected, and none of these corresponded to constitutively activating point mutations that have been used in cell lines for transformation. While sequencing Rac1 in breast tissues, a new Rac1 isoform with an insertion of 19 codons within the reading frame of Rac1 close to switch region II was identified and named Rac1b. The Rac1b protein acts like a fast cycling GTPase in GTP binding and hydrolysis assays. In Northern and Western blot experiments both Rac1 RNA and Rac1 protein had a significantly higher expression in breast cancer tissues compared to normal breast tissue samples. Immunohistochemical staining of Rac1 showed weak Rac1 expression in benign breast disease but high expression level in ductal carcinoma-in-situ, primary breast cancer, and lymph node metastases. In addition, breast tumor cells from patients with recurrent disease had Rac1 expression at the plasma membrane, suggesting activation of Rac1, in patients with aggressive breast cancer. Oncogene (2000).
Abstract
Background/Introduction
Sarcoidosis is a multi-systemic disorder of unknown etiology, characterized by the presence of non-caseating granulomas in target organs. In 90% of cases, there is ...thoracic involvement. Fifty to seventy percent of pulmonary sarcoidosis patients will experience acute, self-limiting disease. For the subgroup of patients who develop persistent disease, no targeted therapy is currently available.
Aim
To investigate the potential of the single nucleotide polymorphism (SNP), Toll-like receptor 3 Leu412Phe (TLR3 L412F; rs3775291), as a causative factor in the development of and in disease persistence in pulmonary sarcoidosis. To investigate the functionality of TLR3 L412F in vitro in primary human lung fibroblasts from pulmonary sarcoidosis patients.
Design
SNP-genotyping and cellular assays, respectively, were used to investigate the role of TLR3 L412F in the development of persistent pulmonary sarcoidosis.
Methods
Cohorts of Irish sarcoidosis patients (n = 228), healthy Irish controls (n = 263) and a secondary cohort of American sarcoidosis patients (n = 123) were genotyped for TLR3 L412F. Additionally, the effect of TLR3 L412F in primary lung fibroblasts from pulmonary sarcoidosis patients was quantitated following TLR3 activation in the context of cytokine and type I interferon production, TLR3 expression and apoptotic- and fibroproliferative-responses.
Results
We report a significant association between TLR3 L412F and persistent clinical disease in two cohorts of Irish and American Caucasians with pulmonary sarcoidosis. Furthermore, activation of TLR3 in primary lung fibroblasts from 412 F-homozygous pulmonary sarcoidosis patients resulted in reduced IFN-β and TLR3 expression, reduced apoptosis- and dysregulated fibroproliferative-responses compared with TLR3 wild-type patients.
Discussion/Conclusion
This study identifies defective TLR3 function as a previously unidentified factor in persistent clinical disease in pulmonary sarcoidosis and reveals TLR3 L412F as a candidate biomarker.
Members of the Rho family of small GTPases have been shown to be involved in tumorigenesis and metastasis. Currently, most of the available information on the function of Rho proteins in malignant ...transformation is based on the use of dominant-negative mutants of these GTPases. The specificity of these dominant-negative mutants is limited however. In this study, we used small interfering RNA directed against either Rac1 or Rac3 to reduce their expression specifically. In line with observations using dominant-negative Rac1 in other cell types, we show that RNA interference-mediated depletion of Rac1 strongly inhibits lamellipodia formation, cell migration and invasion in SNB19 glioblastoma cells. Surprisingly however, Rac1 depletion has a much smaller inhibitory effect on SNB19 cell proliferation and survival. Interestingly, whereas depletion of Rac3 strongly inhibits SNB19 cell invasion, it does not affect lamellipodia formation and has only minor effects on cell migration and proliferation. Similar results were obtained in BT549 breast carcinoma cells. Thus, functional analysis of Rac1 and Rac3 using RNA interference reveals a critical role for these GTPases in the invasive behavior of glioma and breast carcinoma cells.
Pike perch (Sander lucioperca) has been identified as specie destined to diverse European inland aquaculture, but knowledge on the nutritional requirements is weak. Therefore, we investigated the ...effect of varying dietary fatty acid (FA) profile by partial replacement of fish oil (FO) with vegetable oils on growth, FA and body composition of juvenile pike perch. An extruded basal diet containing 59 g kg-1 crude lipids (FO) was added with 60 g kg-1 FO, 60 g kg-1 linseed oil (LO) or 60 g kg-1 soybean oil (SO). The resulting dietary FA composition differed mainly in the triglyceride fraction and was characterized by highest amounts of linolenic acid (18:3 n-3) in the LO diet and linoleic acid in the SO diet. Diet enriched with FO contained highest contents of highly unsaturated FA 20:5 n-3 (eicosapentaenic acid) and 22:6 n-3 (docosahexaenic acid). Pike perch were held in a recirculation system and each feeding group (in triplicate) was fed with experimental diets at a daily rate of 35 g kg-1 of biomass for 57 days by automatic feeders. Weight gain and specific growth rate of experimental feeding groups ranged between 18.47 and 19.58 g and 1.37-1.45% day-1 and was not affected by the dietary composition indicating that FO can be replaced by vegetable oils without negative impact on growth performance. In contrast to the whole body and muscle composition, liver tissue was affected by the varying diets. Liver tissues of fish fed diets enriched with vegetable oils showed significantly increased lipid contents of 162 (LO) and 147 (SO) g kg-1 and indicate decreased lipid utilization compared with fish fed FO diet (liver lipid content 112 g kg-1). Nevertheless, hepatosomatic index of pike perch was not influenced by dietary lipid composition. The FA profile of pike perch was generally determined by the dietary FAs.
The effect of juvenile Nile tilapia (Oreochromis niloticus, in unit I) and Common carp (Cyprinus carpio, in unit II) on plant growth (cucumber - Cucumis sativus, tomato - Solanum lycopersicum and ...lettuce - Lactuca sativa in co-cultivation) was investigated in two identical gravel substrate ebb-and-flood coupled aquaponic units (I, II) with 3.81m3 total water volume and without addition of fertiliser for 70days. The daily extruded floating feed input of 1.2% (200g) of initial fish biomass (16.7kg) per unit equalled 12.0g feed per kg fish or 52.5gm−3. Growth of O. niloticus (unit I) was better (p<0.05) in final weight (57.4g±27.9), final biomass (27,683.3g±160.7), specific growth rate (0.70%d−1±0.01) and feed conversion ratio (1.31±0.02) in comparison to C. carpio (unit II, 42.7g±22.2, 21,866.7g±568.6, 0.39%d−1±0.02, 2.69±0.20). Tomato gross biomass was two times higher in combination with O. niloticus and tomato fruit weight was slightly higher. Plant growth in cucumber showed higher total fresh biomass in the C. carpio unit. Lettuce yield was near zero as a result of inter-specific competition. The Aquaponic Growth Factor (AGF), describing the growth performance of fish and plant combinations, was highest in tomato (1.12) combined with O. niloticus compared with C. carpio (0.53). However, the AGF of cucumber was slightly higher in combination with C. carpio (0.14) compared with O. niloticus (0.12). This study demonstrates best plant growth for the combination of O. niloticus with tomato and C. carpio with cucumber. The unit stocked with C. carpio had higher levels of oxygen (6.3mgL−1±0.8) and oxygen saturation (78.6%±8.4) in contrast to O. niloticus (5.8mgL−1±0.8, 73.2%±8.9). The long steady state of dissolved oxygen inside both units allowed a higher daily feed input of 0.3% of fish initial biomass during spring and summer seasons, 25% above the optimal feed input estimated for the same units during winter time (0.9%=150g). C. carpio extended the equilibrium phase during plant production before a significant oxygen drop occurred, beneficial for coupled aquaponics. Different growth performance of fish and plant combinations suggest multiple fish species use or polyponics (polyculture+aquaponics) in coupled aquaponics to increase plant yield.
Different fish species used in identical aquaponic systems change oxygen levels and alter plant species growth. We herewith confirm this for two further fish species, and suggest combined fish species cultivation (polyponics) in coupled aquaponics to increase plant performance.
•Aquaponics of vegetables showed best plant growth combining of Nile tilapia (Oreochromis niloticus) with tomato (Solanum lycopersicum)•Cucumber fresh biomass tended to have a higher yield in combination with Common carp (Cyprinus carpio)•Diametrical fish and plant growth suggests multiple fish species use or polyponics (polyculture+aquaponics)•Less oxygen use of Carp in comparison with Tilapia extended the stable performance of the coupled aquaponics•Summer conditions allowed 25% higher fish feed input compared with winter conditions
The Rac guanosine 5′-triphosphate (GTP)-binding proteins regulate oxidant production by phagocytic leukocytes. Two Ste20-related p21-activated kinases (PAKs) were identified as targets of Rac in ...human neutrophils. Activity of the ∼65-and ∼68-kilodalton PAKs was rapidly stimulated by chemoattractants acting through pertussis toxin-sensitive heterotrimeric GTP-binding proteins (G proteins). Native and recombinant PAKs phosphorylated the p47$^{phox}$ reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase component in a Rac-GTP-dependent manner. The action of PAKs during phagocyte activation by G protein-coupled pathways may contribute to regulation of NADPH oxidase activity.
Background: The Rho family GTPases Cdc42, Rac1 and RhoA regulate the reorganization of the actin cytoskeleton induced by extracellular signals such as growth factors. In mammalian cells, Cdc42 ...regulates the formation of filopodia, whereas Rac regulates lamellipodia formation and membrane ruffling, and RhoA regulates the formation of stress fibers. Recently, the serine/threonine protein kinase p65pak autophosphorylates, thereby increasing its catalytic activity towards exogenous substrates. This kinase is therefore a candidate effector for the changes in cell shape induced by growth factors.
Results: Here, we report that the microinjection of activated Pak1 protein into quiescent Swiss 3T3 cells induces the rapid formation of polarized filopodia and membrane ruffles. The prolonged overexpression of Pak1 amino-terminal mutants that are unable to bind Cdc42 or Rac1 results in the accumulation of filamentous actin in large, polarized membrane ruffles and the formation of vinculin-containing focal complexes within these structures. This phenotype resembles that seen in motile fibroblasts. The amino-terminal Pak1 mutant displays enhanced binding to the adaptor protein Nck, which contains three Src-homology 3 (SH3) domains. Mutation of a proline residue within a conserved SH3-binding region at the amino terminus of Pak1 interferes with SH3-protein binding and alters the effects of Pak1 on the cytoskeleton.
Conclusions: These results indicate that Pak1, acting through a protein that contains an SH3 domain, regulates the structure of the actin cytoskeleton in mammalian cells, and may serve as an effector for Cdc42 and/or Rac1 in promoting cell motility.
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