Effects of Pulsed Electromagnetic Fields of Different Frequencies on the Gene Expression of RANK and NFATc1 in Rat Osteoclasts Co-Cultured with Osteoblasts

The study investigated the effects of pulsed electromagnetic fields (PEMFs) of different frequencies on the gene expression of receptor activator of nuclear factor kappa B (RANK) and Nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) in rat osteoblast and osteoclast co-cultured model. Osteoblast-like cells were isolated from calvariae of Newborn Sprague Dawley rats (SD rats), while osteoclast-like cells were obtained from femora and tibiae of five weeks old SD rats. After 1 days of co-culture, the cells were exposed to premarin (E2) and different frequencies of PEMFs (8 Hz and 16 Hz, respectively) for 3 days. The expression of RANK and NFATc1 mRNA was analysed with realtime quantitative polymerase chain reaction. The gene expression of RANK and NFATc1 in the E2, PEMF with 8 Hz and 16 Hz group was significantly lower than that in the control group respectively. The gene expression of NFATc1 in the PEMF with 8 Hz group was significantly lower than that in the control group and PEMF with 16 Hz group. The study indicates that PEMF with 8 Hz could regulate the gene expression of RANK and NFATc1 in co-cultured model.

Histological observation on acellular nerve grafts co-cultured with Schwann cells for repairing defects of the sciatic nerve

BACKGROUND： Animal experiments and clinical studies about tissue engineering method applied to repair nerve injury mainly focus on seeking ideal artificial nerve grafts, nerve conduit and seed cells. Autologous nerve, allogeneic nerve and xenogeneic nerve are used to bridge nerve defects, it is one of the methods to promote the repair of nerve injury by culturing and growing Schwann cells, which can secrete various neurotrophic factor activities, in the grafts. OBJECTIVE ： To observe the effect of acellular nerve grafts co-cultured with Schwann cells in repairing defects of sciatic nerve. DESIGN： An observational comparative study.SETTING： Tissue Engineering Laboratory of China Medical University.MATERIALS： The experiment was carried out in the Tissue Engineering Laboratory of China Medical University between April 2004 and April 2005. Forty neonatal Sprague-Dawley rats of 5-8 days （either males or females） and 24 male Wistar rats of 180-220 g were provided by the experimental animal center of China Medical University. METHODS： ① Culture of Schwann cells： The bilateral sciatic nerves and branchial plexus were isolated from the 40 neonatal SD rats. The sciatic nerves were enzymatically digested with collagenase and dispase, isolatd, purified and cultured with the method of speed-difference adhersion, and identified with the SABC immunohistochemical method. ② Model establishment： In vitro Schwann cells were microinjected into 10-mm long acellular nerve grafts repairing a surgically created gap in the rat sciatic nerve. According to the different grafted methods, the animals were randomly divided into three groups： autografts （n=8）, acellular nerve grafts （n=8）, or acellular nerve grafts with Schwann cells （n=8）. ③ The regenerated nerve fiber number and average diameter of myeline sheath after culture were statistically anlayzed. MAIN OUTCOME MEASURES： ① The regenerated nerve ultrastructure, total number and density of myelinated nerve fibers, and the thickness of myeline sheath were observed under electron microscope. ② The images were processed with the Mias-1000 imaging analytical system to calculate the number of myelinated nerve fibers, and the thickness of myeline sheath. RESULTS： All the 24 Wistar rats were involved in the analysis of results. ① Results observed under transmission electron microscope： The regenerated myelinated nerve fibers in the group of acellular nerve grafts with Schwann cells were more even than those in the group of acellular nerve grafts, the number of myelinated nerve fibers and thickness of myelin sheath were close to those in the allografts group （P 〉 0.05）, but significantly different from those in the group of acellular nerve grafts （P 〈 0.05）. ② Results observed under scanning electron microscope： A great amount of Schwann cells with two polars were observed in the group of grafts with Schwann cells, the feature of cultured Schwann cells showed shoulder by shoulder, head to head. ③ The number of myelinated nerve fibers and thickness of myelin sheath analyzed by Mias-1000 imaging system in the group of acellular nerve grafts with Schwann cells were close to those in the autografts group （P 〉 0.05）, but significantly different from those in the group of acellular nerve grafts （P 〈 0.05）.CONCLUSION： Host axonal regeneration is significantly increased after implant of acellular nerve grafts. Acellular nerve grafts with Schwann cells offers a novel approach for repairing the gap of nerve defect.

The Skin Whitening Effect of Co-Cultured Conditioned Medium: Involvement of Synergy between Stem Cells and Immune Cells

Many researchers have described that mesenchymal stem cells conditioned medium and immune cells conditioned medium have a clear whitening effect when they are used as cosmetic ingredients. In this study, we confirmed the whitening efficacy of various concentrations of immune cells and stem cell conditioned media. The author tried to study a conditioned medium that has a strong whitening effect even with a composition of less than 20% (the most used concentration in cosmetics). Because of the fact that the conditioned medium contains various cytokines and growth factors secreted by stem cells or immune cells, it is known to have effects such as wound healing, antioxidant, and whitening effect. Recently, stem cells have been used not only in the development of cosmetic raw materials but also in skincare procedures, and there are reports being released of cosmetics using immune cells conditioned medium. The concentration-dependent whitening effect equivalently increased as the concentration of the mono-cultured conditioned medium was obtained through the stem cells or immune cells culture. In the case of co-culture, whitening results are like the effect of positive control such as arbutin in the medium carrying only 10% of the co-cultured conditioned medium. It is possible that enhanced whitening efficiency in co-cultured conditioned medium leads to a major innovation in the global cosmetic market.

Probiotic modulation of dendritic cells co-cultured with intestinal epithelial cells

AIM： To investigate cytokine production and cell surface phenotypes of dendritic cells （DC） in the presence of epithelial cells stimulated by probiotics.METHODS： Mouse DC were cultured alone or together with mouse epithelial cell monolayers in normal or in- verted systems and were stimulated with heat-killed probiotic bacteria, Bifidobacterium lactis ADO 11 （BL）, Bifidobacterium bilfidum BGN4 （BB）, Lactobacillus casei IBS041 （LC）, and Lactobacillus acidophilus AD031 （LA）, for 12 h. Cytokine levels in the culture supernatants were determined by enzyme-linked immunosorbent as say and phenotypic analysis of DC was investigated by flow cytometry.RESULTS： BB and LC in singlecultured DC increased the expression of I-Ad, CD86 and CD40 （I-Ad, 18.51 vs 30.88, 46.11, CD86, 62.74 vs 92.7, 104.12; CD40, 0.67 vs 6.39, 3.37, P 〈 0.05）. All of the experimental probiot-ics increased the production of inflammatory cytokines, interleukin （IL）-6 and tumor necrosis factor （TNF）-α. However, in the normal coculture systems, LC and LA decreased the expression of I-A^α （39.46 vs 30.32, 33.26, P 〈 0.05）, and none of the experimental probiotics increased the levels of IL-6 or TNF-α. In the inverted coculture systems, LC decreased the expression of CD40 （1.36 vs -2.27, P 〈 0.05）, and all of the experimental probiotics decreased the levels of IL-6. In addition, BL increased the production of IL-10 （103.8 vs 166.0, P 〈 0.05） and LC and LA increased transforming growth factor-13 secretion （235.9 vs 618.9, 607.6, P 〈 0.05）.CONCLUSION： These results suggest that specific pro- biotic strains exert differential immune modulation mediated by the interaction of dendritic cells and epithelial cells in the homeostasis of gastrointestinal tract.

Protective effects of ACLF sera on metabolic functions and proliferation of hepatocytes co-cultured with bone marrow MSCs in vitro

AIM： To investigate whether the function of hepatocytes co-cultured with bone marrow mesenchymal stem cells （MSCs） could be maintained in serum from acute-on- chronic liver failure （ACLF） patients.METHODS： Hepatocyte supportive functions and cy- totoxicity of sera from 18 patients with viral hepatitis B-induced ACLF and 18 healthy volunteers were evalu- ated for porcine hepatocytes co-cultured with MSCs and hepatocyte mono-layered culture, respectively. Chemo- kine profile was also examined for the normal serum and liver failure serum.RESULTS： Hepatocyte growth factor （HGF） and Tumor necrosis factor; tumor necrosis factor （TNF）-a were re- markably elevated in response to ACLF while epidermal growth factor （EGF） and VEGF levels were significantly decreased. Liver failure serum samples induced a higher detachment rate, lower viability and decreased liver sup- port functions in the homo-hepatocyte culture. Hepato-cytes co-cultured with MSCs could tolerate the cytotoxic- ity of the serum from ACLF patients and had similar liver support functions compared with the hepatocytes cul- tured with healthy human serum in vitro. In addition, co- cultured hepatocytes maintained a proliferative capability despite of the insult from liver failure serum.CONCLUSION： ACLF serum does not impair the cell morphology, viability, proliferation and overall metabolic capacities of hepatocyte co-cultured with MSCs in vitro.

Puerarin exhibits greater distribution and longer retention time in neurons than astrocytes in a co-cultured system

The phytoestrogen puerarin has been shown to protect neurons and astrocytes in the brain, and is therefore an attractive drug in the treatment of Alzheimer’s disease, Parkinson’s disease and cerebral ischemia. Whether puerarin exhibits the same biological processes in neurons and astro-cytesin vitro has rarely been reported. In this study, cortical neurons and astrocytes of newborn Sprague-Dawley rats were separated, identiifed and co-cultured in a system based on Transwell membranes. The retention time and distribution of puerarin in each cell type was detected by lfuorescence spectrophotometry and lfuorescence microscope. The concentration of puerarin in both co-cultured and separately cultured neurons was greater than that of astrocytes. Puerarin concentration reached a maximum 20 minutes after it was added. At 60 minutes after its addi-tion, a scant amount of drug was detected in astrocytes; however in both separately cultured and co-cultured neurons, the concentration of puerarin achieved a stable level of about 12.8 ng/mL. The results indicate that puerarin had a higher concentration and longer retention time in neu-rons than that observed in astrocytes.

Science Letters:Cellular growth under hydrostatic pressure using bovine aortic EC-SMC co-cultured ePTFE vascular graft

High blood pressure (hypertension) is implicated in the development of atherosclerosis. Blood vessels are constantly subjected to stretch due to blood pressure and changes in stretch usually instigate adaptive vascular remodeling, including abnormal growth and proliferation of vascular smooth muscle cells (VSMCs) as well as extracellular matrix (ECM). In this experiment, we used bovine aortic endothelial cells and smooth muscle cells (EC-SMC) co-cultured ePTFE vascular grafts subjected to normal atmospheric pressure (as a control), and 100 mmHg hydrostatic pressure for 7 d. The increase of cell layer thickness was observed. When measured, the cell layer thickness increased by 116.2%. The increase of collagen (Type Ⅳ)synthesis was also observed in the immunohistochemistry assay. When stained with toluidine blue, the cells showed metachromatic phenomenon.

Pre-degenerated peripheral nerves co-cultured with bone marrow-derived cells: a new technique for harvesting high-purity Schwann cells

Schwann cells play an important role in the peripheral nervous system, especially in nerve repair following injury, so artificial nerve regen- eration requires an effective technique for obtaining purified Schwann cells. In vivo and in vitro pre-degeneration of peripheral nerves have been shown to obtain high-purity Schwann cells. We believed that in vitro pre-degeneration was simple and controllable, and available for the clinic. Thus, we co-cultured the crushed sciatic nerves with bone marrow-derived cells in vitro. Results demonstrated that, 3 hours after injury, a large number of mononuclear cells moved to the crushed nerves and a large number of bone marrow-derived cells infiltrated the nerve segments. These changes promoted the degradation of the nerve segments, and the dedifferentiation and proliferation of Schwann cells. Neural cell adhesion molecule and glial fibrillary acidic protein expression were detected in the crushed nerves. Schwann cell yield was 9.08 ± 2.01 ×104/mg. The purity of primary cultured Schwann cells was 88.4 ± 5.79%. These indicate a successful new method for ob- taining Schwann cells of high purity and yield from adult crushed sciatic nerve using bone marrow-derived cells.

A Preliminary Observation on the Development of Mouse Embryos Co-cultured with Human Oviductal Tissue or Conditioned Medium in Vitro

The present investigation has been carried out to examine the effect of human oviductaltissue co-culture system on the development of mouse embryos in vitro. Two-cell embryos collected from superovulated mouse were co-cultured with human oviductal tissue suspended inHam 's F10+10% Fetal Calf Serum(F10 FCS),or,in oviductal tissue conditioned medium andF10 FCS as control.The results showed that the proportion developed into blastocyst,proportion of hatchedand the velocity of embryo development were higher in both tissue co-culture and conditionedmedium as compared with F10 FCS control. Furthermore,the velocity and percentage ofembryomic development were higher in co-culture with ampullary tissue or its conditioned medium than that of isthmus.The effects of co-culture and conditioned medium on embryo development had no significant difference. All the embryos obtained from two co-culture systemscould cleave normally.This experimental observation indicated that human oviductalepithelium might secrete some factors to promote the embryonic development in vitro.

New Antibacterial Dihydropyrones Induced by Co-Culture of Penicillium crustosum PRB-2 and Penicillium citrinum HDN11-186

Two new dihydropyrones,rhytismatones C(1)and D(2),and a known compound,penicillenol A1(3),were isolated from the co-culture broth of the deep-sea-derived fungus Penicillium crustosum PRB-2 and Suaeda salsa-derived endophytic fungus Peni-cillium citrinum HDN11-186.Their structures were elucidated through comprehensive analysis of nuclear magnetic resonance(NMR)spectra and mass spectra.The absolute configurations of new compounds were determined by calculating the electronic circular di-chroism(ECD)spectrum.UPLC-MS data showed that compounds 1–3 could only be detected in the media of co-culture,suggesting new biosynthetic pathways were activated in the co-cultured fungi.Compound 1 showed obvious antibacterial activities against Pro-teus sp.MMBC-1002 and Bacillus subtilis MMBC-1004 with minimum inhibitory concentration(MIC)both at 25μmolL^(-1).

Fibroblasts weaken the anti-tumor effect of gefitinib on co-cultured non-small cell lung cancer cells

Background Non-small cell lung cancer （NSCLC） is the most common lung malignancy worldwide.The metastatic potential of NSCLC cells has been shown to be associated with the tumor microenvironment,which consists of tumor cells,stroma,blood vessels,immune infiltrates and the extracellular matrix.Fibroblasts can produce numerous extraceilular matrix molecules and growth factors.Gefitinib has been evaluated as a first-line treatment in selected patients,and it has shown favorable efficacy especially in NSCLC,but it is not effective for everyone.Methods In this study,we examined the antitumor activity of gefitinib on lung fibroblasts co-cultured of lung cancer cells.A series of co-culture experiments that employed cell counting kit-8 （CCK8）,transwells,real-time polymerase chain reaction （RT-PCR） and Western blotting with HFL-1 fibroblasts and A549 human lung carcinoma cells were performed to learn more about tumor cell proliferation,migration and invasion; and to determine any change of epithelial mesenchymal transition （EMT）-associated tumor markers vimentin,matrix metallopro-teinase 2 （MMP2） and chemotaxis cytokines receptor 4 （CXCR4） mRNA levels.Results A549 cell proliferation in the presence of HFL-1 cells was not significantly increased compared with A549 cells alone,but A549 cell spheroid body formation was increased after co-culture,and treatment with gefitinib increased further.Our study also revealed that fibroblasts attenuated the lung cancer cell inhibition ratio of migration and invasion after gefitinib treatment in vitro.To further study this mechanism,RT-PCR analysis showed that vimentin,MMP2 and CXCR4 mRNA levels were more highly expressed in the lung cancer cells after co-culture,but did not obviously decrease compared with the control cells following gefitinib treatment.This suggests the mechanism by which fibroblasts attenuate gefitinib-induced expression of EMT-associated tumor markers.Finally,our results demonstrated that co-culture with A549 lung cancer cells does not alter the cell cycle distribution of HFL-1 fibroblasts.Furthermore,HFL-1 fibroblasts had no effect on the cell cycle distribution of HFL-1 cells treated with gefitinib.Conclusion Gefitinib has lower anti-tumor activity on A549 lung cancer cells when co-cultured with HFL-1 fibroblasts.

Co-cultured adventitious roots of Echinacea pallida and Echinacea purpurea inhibit lipopolysaccharide-induced inflammation via MAPK pathway in mouse peritoneal macrophages

Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory activities and potential mechanisms of Co-cultured ARs were studied.Methods:The experimental materials were obtained by bioreactor co-culture technology and used in the activity research.In this study,mouse macrophages induced by lipopolysaccharide(LPS) were used as in vitro model.Different concentrations of AR extract(50-400 g/mL) were used to treat cells.The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay.The inducible nitric oxide synthase and cyclooxygenase-2 expression,mitogen-activated protein kinase(MAPK) phosphorylation,and the inhibitor of nuclear factor-kappa B-a levels were determined by the Western blot analysis.Results:In the co-cultured ARs,total flavonoids and total caffeic acid were determined,and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture.Compared with the control group,the large amount of pro-inflammatory mediators was released after LPS stimulation.However,in the extract groups with different concentrations(25,50,and 100 g/mL),the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner.Furthermore,the levels of phosphorylation of MAPK proteins,including p-p38, p-c-Jun N-terminal kinase,and p-extracellular regulated protein kinases were significantly(P <0.05) decreased in the extract groups,revealing that the AR extract probably involved in regulating the MAPK signaling pathway.Conclusion:Collectively,our findings suggested that the co-cultured ARs of E.pallida and E.purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.

“Co-culture Engineering”for Enhanced Phytoremediation of Metal Contaminated Soils

A co-culture of two plant materials, Astragalus sinicus L., a leguminous plant with concomitant nodules, and Elsholtzia splendens Naki-a Cu accumulator, along with treatments of a chelating agent (EDTA), root excretions (citric acid), and a control with E. splendens only were used to compare the mobility of heavy metals in chelating agents with a co-culture and to determine the potential for co-culture phytoremediation in heavy metal contaminated soils. The root uptake for Cu, Zn, and Pb in all treatments was significantly greater (P ＜ 0.05) than that of the control treatment. However with translocation in the shoots, only Cu, Zn, and Pb in plants grown with the EDTA treatment and Zn in plants cocropped with the A. sinicus treatment increased significantly (P ＜ 0.05). In addition, when a co-culture in soils with heavy and moderate contamination was compared, for roots in moderately contaminated soils only Zn concentration was significantly less (P ＜ 0.05) than that of heavily contaminated soils, however, Cu, Zn, and Pb concentrations of shoots were all significantly lower (P ＜ 0.05). Overall, this 'co-culture engineering' could be as effective as or even more effective than chelating agents, thereby preventing plant metal toxicity and metal leaching in soils as was usually observed in chelate-enhanced phytoremediation.

Rice-duck co-culture benefits grain 2-acetyl-1-pyrroline accumulation and quality and yield enhancement of fragrant rice

Rice-duck co-culture is an integrated farming technology that benefits rice production, grain quality, and ecological sustainability in paddy fields. However, little is known about the effects of rice-duck co-culture on enzyme activity involved in the biosynthesis of 2-acetyl-1-pyrroline (2-AP), the volatile that gives fragrant rice its' distinctive and sought-after aroma. The present study aimed to examine the influence of rice-duck co-culture on the photosynthesis, yield, grain quality, rice aroma, and the enzymes involved in 2-acetyl-1-pyrroline biosynthesis in the cultivar Meixiangzhan 2 during the early and late rice growing seasons of 2016 in Guangzhou, China. We compared the rice grown in paddy fields with and without ducks. We found that rice-duck co-culture not only improved the yield and quality of fragrant rice grain, but also promoted the precursors of 2-AP biosynthesis formation and 2-AP accumulation in the grain. Grain 2-AP content in rice-duck co-culture was noticeably increased with 9.60% and 20.81% in early and late seasons, respectively. Proline and pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP biosynthesis) and the activity of enzymes such as proline dehydrogenase (ProDH), ornithine aminotransferase (OAT) and Δ1 pyrroline-5-carboxylic acid synthetase (P5CS) were all improved by 10.15%–12.99%, 32.91%–47.75%, 17.81%–26.71%, 6.25%–21.78%, and 10.58%–38.87% under rice-duck co-culture in both seasons, respectively. Overall, our results suggest that rice-duck co-culture is an environmentally-friendly and sustainable approach to improving rice aroma and grain quality of fragrant rice.

Promoted differentiation of cynomolgus monkey ES cells into hepatocyte-like cells by co-culture with mouse fetal liver-derived cells

AIM: To explore whether a co-culture of cynomolgus monkey embryonic stem (cES) cells with embryonic liver cells could promote their differentiation into hepatocytes. METHODS: Mouse fetal liver-derived cells (MFLCs) were prepared as adherent cells from mouse embryos on embryonic d (ED) 14, after which undifferentiated cES cells were co-cultured with MFLCs. The induction of cES cells along a hepatic lineage was examined in MFLC- assisted differentiation, spontaneous differentiation, and growth factors (GF) and chemicals-induced differentiations (GF-induced differentiation) using retinoic acid, leukemia inhibitory factor (LIF), FGF2, FGF4, hepatocyte growth factor (HGF), oncostatin M (OSM), and dexamethasone. RESULTS: The mRNA expression of α-fetoprotein, albumin (ALB), α-1-antitrypsin, and hepatocyte nuclear factor 4α was observed earlier in the differentiating cES cells co-cultured with MFLCs, as compared to cES cells undergoing spontaneous differentiation and those subjected to GF-induced differentiation. The expression of cytochrome P450 7a1, a possible marker for embryonic endoderm-derived mature hepatocytes, was only observed in cES cells that had differentiated in a co-culture with MFLCs. Further, the disappearance of Oct3/4, a representative marker of an undifferentiated state, was noted in cells co-cultured with MFLCs, but not in those undergoing spontaneous or GF-induced differentiation. Immunocytochemical analysis revealed an increased ratio of ALB-immunopositive cells among cES cells co-cultured with MFLCs, while glycogen storageand urea synthesis were also demonstrated. CONCLUSION: MFLCs showed an ability to induce cES cells to differentiate toward hepatocytes. The co-culture system with MFLCs is a useful method for induction of hepatocyte-like cells from undifferentiated cES cells.

In vitro model of the blood-brain barrier established by co-culture of primary cerebral microvascular endothelial and astrocyte cells

Drugs for the treatment and prevention of nervous system diseases must permeate the bloodbrain barrier to take effect.In vitro models of the blood-brain barrier are therefore important in the investigation of drug permeation mechanisms.However,to date,no unified method has been described for establishing a blood-brain barrier model.Here,we modified an in vitro model of the blood-brain barrier by seeding brain microvascular endothelial cells and astrocytes from newborn rats on a polyester Transwell cell culture membrane with 0.4-μm pores,and conducted transepithelial electrical resistance measurements,leakage tests and assays for specific bloodbrain barrier enzymes.We show that the permeability of our model is as low as that of the bloodbrain barrier in vivo.Our model will be a valuable tool in the study of the mechanisms of action of neuroprotective drugs.

Effects of Rice-Fish Co-culture on Oxygen Consumption in Intensive Aquaculture Pond

Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.

Impact of Rice-Catfish/Shrimp Co-culture on Nutrients Fluxes Across Sediment-Water Interface in Intensive Aquaculture Ponds

Exchange of nitrogen and phosphorus across sediment-water interface plays an important role in the management of nutrient recycling in the aquaculture pond. In this study, a plot experiment was conducted to study the effect of rice-catfish/shrimp co-culture on the micro-profile of oxygen (O2), pH and nutrient exchange across sediment-water interface in the intensive culture ponds. The results showed that rice-catfish co-culture increased the concentration and penetrating depth of O2, but decreased the pH value across the sediment-water interface, compared with catfish monoculture. Additional rice cultivation significantly reduced the flux rates of ammonium (NH4+) and nitrate (NO3-) across sediment-water interface in the catfish and shrimp ponds. The flux rates of NO2 - and soluble phosphorus (PO43-) showed no significant difference between rice-catfish/shrimp co-culture ponds and catfish/shrimp monoculture ponds. Rice only affected the dissolved inorganic nitrogen and phosphorus fractions in the sediment. The concentrations of NH4 + were significantly lower in the sediment of co-culture ponds than in the monoculture ponds. Additional rice cultivation also significantly reduced the content and percentage of dissolved inorganic phosphorus in the sediment of catfish ponds.

Advances in tumor-endothelial cells co-culture and interaction on microfluidics

The metastasis in which the cancer cells degrade the extracellular matrix （ECM） and invade to the sur- rounding and far tissues of the body is the leading cause of mortality in cancer patients, With a lot of advancement in the field, yet the biological cause of metastasis are poorly understood, The microfluidic system provides advanced technology to reconstruct a variety of in vivo-like environment for studying the interactions between tumor ceils （TCs） and endothelial ceils （ECs）. This review gives a brief account of both two-dimensional models and three-dimensional microfluidic systems for the analysis of TCs-ECs co- culture as well as their applications to anti-cancer drug screening, Furthermore, the advanced methods for analyzing cell-to-cell interactions at single-cell level were also discussed,