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Osteochondral regeneration remains formidable challenges despite significant advances in microsurgery. Herein, an acellular trilayer cryogel (TC) with injectability, tunable pore sizes (80-200 µm), and appropriate compressive modulus (10.8 kPa) is manufactured from self-healable hydrogel under different gelling times through Schiff reaction between chitosan and difunctionalized polyurethane (DFPU). Bioactive molecules (Y27632 and dexamethasone) are respectively loaded in the top and bottom layers to form the Y27632/dexamethasone-loaded trilayer cryogel (Y/DEX-TC). Mesenchymal stem cells (MSCs) seeded in Y/DEX-TC proliferated ≈350% in vitro and underwent chondrogenesis or osteogenesis in response to the respective release of Y or DEX in 14 days. Acupuncture is administered to animals in an attempt to modulate the innate regulatory system and mobilize endogenous MSCs for osteochondral defect regeneration. In vivo rabbit experiments using Y/DEX-TC combined with acupuncture successfully regulate SDF-1 and TGF-ß1 levels, which possibly cause MSC migration toward Y/DEX-TC. The synergistic effect of cryogel and acupuncture on immunomodulation is verified with a ≈7.3-fold enhancement of the M2-/M1-macrophage population ratio by treatment of Y/DEX-TC combining acupuncture, significantly greater than ≈1.5-fold increase by acupuncture or ≈2.2-fold increase by Y/DEX-TC alone. This novel strategy using acellular drug-loaded cryogel and accessible acupuncture shows promise in treating osteochondral defects of joint damage.
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Hydrogels containing catechol group have received attention in the biomedical field due to their robust adhesive/cohesive capabilities, biocompatibility, and hemostatic abilities. Catechol-functionalized chitosan holds promise for preparing self-assembly hydrogels. However, issues of inefficient gelation and instability still persist in these hydrogels. In the current study, we synthesized chitosan catechol (CC) of high catechol substitution (â¼28 %) and combined CC with tannic acid (TA, which also contains catechol) to form self-healing CC-TA hydrogels. The catechol-enriched CC-TA composite hydrogels showed rapid gelation and mechanical reinforcement (shear modulus â¼110 Pa). In situ coherent small-angle X-ray scattering (SAXS) coupled with rheometry revealed a morphological feature of mesoscale clusters (â¼20 nm) within CC-TA hydrogel. The clusters underwent dynamic destruction under large-amplitude oscillatory shear, corresponding with the strain-dependent and self-healing behavior of the CC-TA hydrogel. The composite hydrogel had osmotic-responsive and notable adhesive properties. Meanwhile, CC-TA composite cryogel prepared simply through freeze-thawing procedures exhibited distinctive macroporous structure (â¼200 µm), high water swelling ratio (â¼7000 %), and favorable compressive modulus (â¼8 kPa). The sponge-like cryogel was fabricated into swabs, demonstrating hemostatic capacity. The CC-TA composites, in both hydrogel and cryogel forms, possessed ROS scavenging ability, antimicrobial activity, and cell compatibility with potentials in biological applications.
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Catecoles , Quitosano , Criogeles , Hemostáticos , Hidrogeles , Taninos , Quitosano/química , Quitosano/farmacología , Catecoles/química , Catecoles/farmacología , Taninos/química , Taninos/farmacología , Criogeles/química , Hidrogeles/química , Hidrogeles/farmacología , Hemostáticos/química , Hemostáticos/farmacología , Antiinfecciosos/farmacología , Antiinfecciosos/química , Animales , ReologíaRESUMEN
The interaction between diverse nanoarchitectured fullerenes and cells is crucial for biomedical applications. Here, we detailed the preparation of hydrophilic self-assembled fullerenes by the liquid-liquid interfacial precipitation (LLIP) method and hydrophilic coating of the materials as a possible vascularization strategy. The interactions of vascular endothelial cells (ECs) with hydrophilic fullerene nanotubes (FNT-P) and hydrophilic fullerene nanowhiskers (FNW-P) were investigated. The average length and diameter of FNT-P were 16 ± 2 µm and 3.4 ± 0.4 µm (i.e. aspect ratios of 4.6), respectively. The average length and diameter of FNW-P were 65 ± 8 µm and 1.2 ± 0.2 µm (i.e. aspect ratios of 53.9), respectively. For two-dimensional (2D) culture after 7 days, the ECs remained viable and proliferated up to ~ 420% and ~ 400% with FNT-P and FNW-P of 50 µg/mL, respectively. Furthermore, an optimized chitosan-based self-healing hydrogel with a modulus of ~400 Pa was developed and used to incorporate self-assembled fullerenes as in vitro three-dimensional (3D) platforms to investigate the impact of FNT-P and FNW-P on ECs within a 3D environment. The addition of FNW-P or FNT-P (50 µg/mL) in the hydrogel system led to proliferation rates of ECs up to ~323% and ~280%, respectively, after 7 days of culture. The ECs in FNW-P hydrogel displayed an elongated shape with aligned morphology, while those in FNT-P hydrogel exhibited a rounded and clustered distribution. Vascular-related gene expressions of ECs were significantly upregulated through interactions with these fullerenes. Thus, the combined use of different nanoarchitectured self-assembled fullerenes and self-healing hydrogels may offer environmental cues influencing EC development in a 3D biomimetic microenvironment, holding promise for advancing vascularization strategy in tissue engineering.
Self-assembled fullerenes with large aspect ratios modulate the morphology and gene expression of endothelial cells within a soft biomimetic 3D microenvironment, representing a promising new vascularization strategy in tissue engineering.
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BACKGROUND: Parkinson's disease (PD) is one of the most common long-term neurodegenerative diseases. Current treatments for PD are mostly based on surgery and medication because of the limitation and challenges in selecting proper biomaterials. In this study, an injectable bioactive hydrogel based on novel tannic acid crosslinker was developed to treat PD. METHODS: The oxidized tannic acid modified gold nano-crosslinker was synthesized and used to effectively crosslink chitosan for preparation of the bioactive self-healing hydrogel. The crosslinking density, conductivity, self-healing ability, and injectability of the hydrogel were characterized. Abilities of the hydrogel to promote the proliferation and differentiation of neural stem cells (NSCs) were assessed in vitro. Anti-inflammatory property was analyzed on J774A.1 macrophages. The hydrogel was injected in the PD rat model for evaluation of the motor function recovery, electrophysiological performance improvement, and histological repair. RESULTS: The hydrogel exhibited self-healing property and 34G (~ 80 µm) needle injectability. NSCs grown in the hydrogel displayed long-term proliferation and differentiation toward neurons in vitro. Besides, the hydrogel owned strong anti-inflammatory and antioxidative capabilities to rescue inflamed NSCs (~ 90%). Brain injection of the bioactive hydrogel recovered the motor function of PD rats. Electrophysiological measurements showed evident alleviation of irregular discharge of nerve cells in the subthalamic nucleus of PD rats administered with the hydrogel. Histological examination confirmed that the hydrogel alone significantly increased the density of tyrosine hydroxylase positive neurons and fibers as well as reduced inflammation, with a high efficacy similar to drug-loaded hydrogel. CONCLUSION: The new bioactive hydrogel serves as an effective brain injectable implant to treat PD and a promising biomaterial for developing novel strategies to treat brain diseases.
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A Correction to this paper has been published: https://doi.org/10.1038/s41556-021-00686-x.
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Unhealed chronic wounds often deteriorate into multiple infection with several kinds of bacteria and excessive proteolytic wound exudate and remains one of the common healthcare issues. Here, the functional and antimicrobial hydrogel and cryogel biomaterials were prepared from glycol chitosan and a novel biodegradable Schiff base crosslinker difunctional polyurethane (DF-PU). The cryogel exhibited ~2730 ± 400% of water absorption with abundant macropores and 86.5 ± 1.6% of porosity formed by ice crystal as well as ~240% cell proliferation effect; while the hydrogel demonstrated considerable antimicrobial activity and biodegradability. As an optimized procedure to treat the diabetic skin wound in a rat model, the combined application of adipose stem cell-seeded cryogel/hydrogel biomaterials on the wound and acupuncture surrounding the wound may attain 90.34 ± 2.3% of wound closure and secure the formation of granulation tissue with sufficient microvessels and complete re-epithelialization in 8 days. The average increases in the superficial temperature of wounded animals after acupuncture were about 1-2 °C. Through the activation of C3a and C5a, the increased secretion of cytokines SDF-1 and TGFß-1, as well as the down-regulation of proinflammatory cytokines TNF-α and IL-1ß, the combined treatment of stem cell-seeded cryogel/hydrogel biomaterials and acupuncture on wounds produced synergistic immunomodulatory effects. The strategy using the combined treatment of biomaterials, stem cells, and acupuncture reveals a perspective new approach to accelerate the tissue regeneration.
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Terapia por Acupuntura , Diabetes Mellitus , Animales , Materiales Biocompatibles , Criogeles , Hidrogeles , Inmunomodulación , Ratas , Piel , Cicatrización de HeridasRESUMEN
Epigenetic modifiers frequently harbor loss-of-function mutations in lung cancer, but their tumor-suppressive roles are poorly characterized. Histone methyltransferase KMT2D (a COMPASS-like enzyme, also called MLL4) is among the most highly inactivated epigenetic modifiers in lung cancer. Here, we show that lung-specific loss of Kmt2d promotes lung tumorigenesis in mice and upregulates pro-tumorigenic programs, including glycolysis. Pharmacological inhibition of glycolysis preferentially impedes tumorigenicity of human lung cancer cells bearing KMT2D-inactivating mutations. Mechanistically, Kmt2d loss widely impairs epigenomic signals for super-enhancers/enhancers, including the super-enhancer for the circadian rhythm repressor Per2. Loss of Kmt2d decreases expression of PER2, which regulates multiple glycolytic genes. These findings indicate that KMT2D is a lung tumor suppressor and that KMT2D deficiency confers a therapeutic vulnerability to glycolytic inhibitors.
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Adenocarcinoma del Pulmón/patología , Proteínas de Unión al ADN/antagonistas & inhibidores , Desoxiglucosa/farmacología , Elementos de Facilitación Genéticos , Regulación Neoplásica de la Expresión Génica , Glucólisis , N-Metiltransferasa de Histona-Lisina/fisiología , Proteína de la Leucemia Mieloide-Linfoide/fisiología , Proteínas de Neoplasias/antagonistas & inhibidores , Adenocarcinoma del Pulmón/tratamiento farmacológico , Adenocarcinoma del Pulmón/metabolismo , Animales , Antimetabolitos/farmacología , Apoptosis , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Proliferación Celular , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Ratones , Ratones Noqueados , Ratones Desnudos , Mutación , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Pronóstico , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The serine/threonine kinase Akt plays a central role in cell proliferation, survival and metabolism, and its hyperactivation is linked to cancer progression. Here we report that Akt undergoes K64 methylation by SETDB1, which is crucial for cell membrane recruitment, phosphorylation and activation of Akt following growth factor stimulation. Furthermore, we reveal an adaptor function of histone demethylase JMJD2A, which is important for recognizing Akt K64 methylation and recruits E3 ligase TRAF6 and Skp2-SCF to the Akt complex, independently of its demethylase activity, thereby initiating K63-linked ubiquitination, cell membrane recruitment and activation of Akt. Notably, the cancer-associated Akt mutant E17K displays enhanced K64 methylation, leading to its hyper-phosphorylation and activation. SETDB1-mediated Akt K64 methylation is upregulated and correlated with Akt hyperactivation in non-small-cell lung carcinoma (NSCLC), promotes tumour development and predicts poor outcome. Collectively, these findings reveal complicated layers of Akt activation regulation coordinated by SETDB1-mediated Akt K64 methylation to drive tumorigenesis.
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Carcinogénesis/metabolismo , Proteína Metiltransferasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ubiquitinación , Células A549 , Animales , Carcinogénesis/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Femenino , Células HEK293 , N-Metiltransferasa de Histona-Lisina , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Lisina/genética , Lisina/metabolismo , Metilación , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Ratones Desnudos , Células 3T3 NIH , Proteína Metiltransferasas/genética , Proteínas Proto-Oncogénicas c-akt/genética , Trasplante HeterólogoRESUMEN
MLL3 and MLL4 are two closely related members of the SET1/MLL family of histone H3K4 methyltransferases and are responsible for monomethylating histone H3K4 on enhancers, which are essential in regulating cell-type-specific gene expression. Mutations of MLL3 or MLL4 have been reported in different types of cancer. Recently, the PHD domains of MLL3/4 have been reported to recruit the MLL3/4 complexes to their target genes by binding to histone H4 during the NT2/D1 stem cell differentiation. Here we show that an extended PHD domain (ePHD6) involving the sixth PHD domain and its preceding zinc finger in MLL3 and MLL4 specifically recognizes an H4H18-containing histone H4 fragment and that modifications of residues surrounding H4H18 modulate H4 binding to MLL3/4. Our in vitro methyltransferase assays and cellular experiments further reveal that the interaction between ePHD6 of MLL3/4 and histone H4 is required for their nucleosomal methylation activity and MLL4-mediated neuronal differentiation of NT2/D1 cells.
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Proteínas de Unión al ADN/metabolismo , Histonas/metabolismo , Dedos de Zinc PHD , Línea Celular Tumoral , Proteínas de Unión al ADN/química , Elementos de Facilitación Genéticos , Células HEK293 , N-Metiltransferasa de Histona-Lisina , Histonas/genética , Humanos , Metilación , Nucleosomas/metabolismo , Unión Proteica/genética , Procesamiento Proteico-PostraduccionalRESUMEN
The stemness maintenance of embryonic stem cells (ESCs) requires pluripotency transcription factors, including Oct4, Nanog, and Sox2. We have previously reported that protein arginine methyltransferase 7 (PRMT7), an epigenetic modifier, is an essential pluripotency factor that maintains the stemness of mouse ESCs, at least in part, by down-regulating the expression of the anti-stemness microRNA (miRNA) miR-24-2. To gain greater insight into the molecular basis underlying PRMT7-mediated maintenance of mouse ESC stemness, we searched for new PRMT7-down-regulated anti-stemness miRNAs. Here, we show that miR-221 gene-encoded miR-221-3p and miR-221-5p are anti-stemness miRNAs whose expression levels in mouse ESCs are directly repressed by PRMT7. Notably, both miR-221-3p and miR-221-5p targeted the 3' untranslated regions of mRNA transcripts of the major pluripotency factors Oct4, Nanog, and Sox2 to antagonize mouse ESC stemness. Moreover, miR-221-5p silenced also the expression of its own transcriptional repressor PRMT7. Transfection of miR-221-3p and miR-221-5p mimics induced spontaneous differentiation of mouse ESCs. CRISPR-mediated deletion of the miR-221 gene, as well as specific antisense inhibitors of miR-221-3p and miR-221-5p, inhibited the spontaneous differentiation of PRMT7-depleted mouse ESCs. Taken together, these findings reveal that the PRMT7-mediated repression of miR-221-3p and miR-221-5p expression plays a critical role in maintaining mouse ESC stemness. Our results also establish miR-221-3p and miR-221-5p as anti-stemness miRNAs that target Oct4, Nanog, and Sox2 mRNAs in mouse ESCs.
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Regulación de la Expresión Génica , MicroARNs/genética , Células Madre Embrionarias de Ratones/citología , Proteína Homeótica Nanog/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Proteína-Arginina N-Metiltransferasas/metabolismo , Factores de Transcripción SOXB1/metabolismo , Animales , Diferenciación Celular , Células Cultivadas , Ratones , Células Madre Embrionarias de Ratones/metabolismo , Proteína Homeótica Nanog/genética , Factor 3 de Transcripción de Unión a Octámeros/genética , Proteína-Arginina N-Metiltransferasas/genética , Factores de Transcripción SOXB1/genéticaRESUMEN
In this work, a novel harvesting strategy using ferrofluids coupled with flocculation as a magnetic directional harvesting system was developed, providing a fast and easy way to effectively collect microalgae with no further modifications made to the ferrofluids. With a ferrofluid dosage of 25mgL-1, a high harvesting efficiency of 95-100% was achieved within 1min. In addition, we successfully performed a wastewater recycling strategy coupled with a microalgal ferrofluid-harvesting dynamic flow-through system to harvest biomass of Chlorella sp. MTF-7 which could achieve over 80% of the maximum level after three repeated recycling cultivations. This work demonstrated the use of an integrated microalgal ferrofluid-harvesting dynamic flow-through system to develop a simple and effective strategy to enhance microalgal harvesting efficiency, along with wastewater recycling, in a marine microalgal Chlorella sp. MTF-7.
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Biocombustibles , Microalgas , Biomasa , Chlorella , FloculaciónRESUMEN
Self-renewal and pluripotency are two fundamental characteristics of embryonic stem cells (ESCs) and are controlled by diverse regulatory factors, including pluripotent factors, epigenetic regulators and microRNAs (miRNAs). Although histone methyltransferases are key epigenetic regulators, whether and how a histone methyltransferase forms a network with miRNAs and the core pluripotent factor system to regulate ESC stemness is little known. Here, we show that the protein arginine methyltransferase 7 (PRMT7) is a pluripotent factor essential for the stemness of mouse ESCs. PRMT7 repressed the miR-24-2 gene encoding miR-24-3p and miR-24-2-5p by upregulating the levels of symmetrically dimethylated H4R3. Notably, miR-24-3p targeted the 3' untranslated regions (UTRs) of the major pluripotent factors Oct4, Nanog, Klf4 and c-Myc, whereas miR-24-2-5p silenced Klf4 and c-Myc expression. miR-24-3p and miR-24-2-5p also targeted the 3'UTR of their repressor gene Prmt7 miR-24-3p and miR-24-2-5p induced mouse ESC differentiation, and their anti-sense inhibitors substantially reversed spontaneous differentiation of PRMT7-depleted mouse ESCs. Oct4, Nanog, Klf4 and c-Myc positively regulated Prmt7 expression. These findings define miR-24-3p and miR-24-2-5p as new anti-pluripotent miRNAs and also reveal a novel epigenetic stemness-regulatory mechanism in which a double-negative feedback loop consisting of PRMT7 and miR-24-3p/miR24-2-5p interplays with Oct4, Nanog, Klf4 and c-Myc to control ESC stemness.
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MicroARNs/fisiología , Células Madre Embrionarias de Ratones/fisiología , Proteína-Arginina N-Metiltransferasas/metabolismo , Regiones no Traducidas 3' , Animales , Secuencia de Bases , Diferenciación Celular , Autorrenovación de las Células , Células Cultivadas , Regulación hacia Abajo , Expresión Génica , Factor 4 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Ratones , Proteína Homeótica Nanog/genética , Proteína Homeótica Nanog/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/genética , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Regiones Promotoras Genéticas , Proteína-Arginina N-Metiltransferasas/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Interferencia de ARNRESUMEN
Histone acetylation, including acetylated H3K14 (H3K14ac), is generally linked to gene activation. Monomethylated histone H3 lysine 4 (H3K4me1), together with other gene-activating marks, denotes active genes. In contrast to usual gene-activating functions of H3K14ac and H3K4me1, we here show that the dual histone modification mark H3K4me1-H3K14ac is recognized by ZMYND8 (also called RACK7) and can function to counteract gene expression. We identified ZMYND8 as a transcriptional corepressor of the H3K4 demethylase JARID1D. ZMYND8 antagonized the expression of metastasis-linked genes, and its knockdown increased the cellular invasiveness in vitro and in vivo. The plant homeodomain (PHD) and Bromodomain cassette in ZMYND8 mediated the combinatorial recognition of H3K4me1-H3K14ac and H3K4me0-H3K14ac by ZMYND8. These findings uncover an unexpected role for the signature H3K4me1-H3K14ac in attenuating gene expression and reveal a metastasis-suppressive epigenetic mechanism in which ZMYND8's PHD-Bromo cassette couples H3K4me1-H3K14ac with downregulation of metastasis-linked genes.
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Movimiento Celular , Metilación de ADN , Regulación Neoplásica de la Expresión Génica , Histonas/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias de la Próstata/metabolismo , Receptores de Superficie Celular/metabolismo , Acetilación , Animales , Sitios de Unión , Línea Celular Tumoral , Proliferación Celular , Regulación hacia Abajo , Histona Demetilasas/genética , Histona Demetilasas/metabolismo , Histonas/genética , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundario , Masculino , Ratones Desnudos , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/metabolismo , Modelos Moleculares , Invasividad Neoplásica , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Unión Proteica , Conformación Proteica , Dominios y Motivos de Interacción de Proteínas , Interferencia de ARN , Receptores de Cinasa C Activada , Receptores de Superficie Celular/genética , Factores de Tiempo , Transcripción Genética , Transfección , Carga Tumoral , Proteínas Supresoras de TumorRESUMEN
The study is focused on the asymmetric secondary freeform lens (ASFL) design for creating a low glared light-emitting diode (LED) street light. The lens is mounted on a chip on board (COB) LED as the new LED street light module to perform a non-axial symmetric light intensity distribution. The experimental results show that the street light can work without inclining lamps and reach Chinese National Standards (CNS) and Illuminating Engineering Society of North America (IESNA) standards at the same time.
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Entire or partial deletions of the male-specific Y chromosome are associated with tumorigenesis, but whether any male-specific genes located on this chromosome play a tumor-suppressive role is unknown. Here, we report that the histone H3 lysine 4 (H3K4) demethylase JARID1D (also called KDM5D and SMCY), a male-specific protein, represses gene expression programs associated with cell invasiveness and suppresses the invasion of prostate cancer cells in vitro and in vivo. We found that JARID1D specifically repressed the invasion-associated genes MMP1, MMP2, MMP3, MMP7, and Slug by demethylating trimethyl H3K4, a gene-activating mark, at their promoters. Our additional results demonstrated that JARID1D levels were highly downregulated in metastatic prostate tumors compared with normal prostate tissues and primary prostate tumors. Furthermore, the JARID1D gene was frequently deleted in metastatic prostate tumors, and low JARID1D levels were associated with poor prognosis in prostate cancer patients. Taken together, these findings provide the first evidence that an epigenetic modifier expressed on the Y chromosome functions as an anti-invasion factor to suppress the progression of prostate cancer. Our results also highlight a preclinical rationale for using JARID1D as a prognostic marker in advanced prostate cancer.
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Transformación Celular Neoplásica/genética , Genes Supresores de Tumor , Histona Demetilasas/genética , Histona Demetilasas/metabolismo , Neoplasias de la Próstata/genética , Animales , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Ratones , Antígenos de Histocompatibilidad Menor , Invasividad Neoplásica , Metástasis de la Neoplasia , Neoplasias de la Próstata/patología , TransfecciónRESUMEN
The development of a culture system for Chlorella sp. GD to efficiently produce biomass and oil for biodiesel production was investigated. Chlorella sp. GD was cultivated with 0%, 25%, 50%, 75% and 100% piggery wastewater (diluted by medium) at 300 µmol m(-2) s(-1), a 2% CO2 aeration rate of 0.2 vvm and 26±1°C; after a 10-day culture in batch cultures, the maximum specific growth rate and biomass productivity of the microalga obtained in 100% piggery wastewater were 0.839 d(-1) and 0.681 g L(-1) d(-1), respectively. The highest lipid content and lipid productivity were 29.3% and 0.155 g L(-1) d(-1) at 25% wastewater, respectively. In semi-continuous cultures, the biomass and lipid productivities with 25-75% wastewater ratios were greater than 0.852 and 0.128 g L(-1) d(-1), respectively. These results show that Chlorella sp. GD grows efficiently in piggery wastewater, and that a stable growth performance was achieved for long-term microalgal cultivation in a semi-continuous culture.
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Biomasa , Chlorella/crecimiento & desarrollo , Lípidos/biosíntesis , Microalgas/crecimiento & desarrollo , Aguas Residuales , Animales , Biodegradación Ambiental , Biocombustibles , Ácidos Grasos/química , Agua Dulce , PorcinosRESUMEN
Using wastewater for microalgal cultures is beneficial for minimizing the use of freshwater, reducing the cost of nutrient addition, removing nitrogen and phosphorus from wastewater and producing microalgal biomass as bioresources for biofuel or high-value by-products. There are three main sources of wastewater, municipal (domestic), agricultural and industrial wastewater, which contain a variety of ingredients. Some components in the wastewater, such as nitrogen and phosphorus, are useful ingredients for microalgal cultures. In this review, the effects on the biomass and lipid production of microalgal Chlorella cultures using different kinds of wastewater were summarized. The use of the nutrients resource in wastewater for microalgal cultures was also reviewed. The effect of ammonium in wastewater on microalgal Chlorella growth was intensively discussed. In the end, limitations of wastewater-based of microalgal culture were commented in this review article.
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Biomasa , Biotecnología/métodos , Chlorella/crecimiento & desarrollo , Lípidos/biosíntesis , Microalgas/crecimiento & desarrollo , Aguas ResidualesRESUMEN
The biomass and lipid productivity of Chlorella sp. MTF-15 cultivated using aeration with flue gases from a coke oven, hot stove or power plant in a steel plant of the China Steel Corporation in Taiwan were investigated. Using the flue gas from the coke oven, hot stove or power plant for cultivation, the microalgal strain obtained a maximum specific growth rate and lipid production of (0.827 d(-1), 0.688 g L(-1)), (0.762 d(-1), 0.961 g L(-1)), and (0.728 d(-1), 0.792 g L(-1)), respectively. This study demonstrated that Chlorella sp. MTF-15 could efficiently utilize the CO2, NOX and SO2 present in the different flue gases. The results also showed that the growth potential, lipid production and fatty acid composition of the microalgal strain were dependent on the composition of the flue gas and on the operating strategy deployed.
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Biodegradación Ambiental , Dióxido de Carbono/química , Chlorella/metabolismo , Residuos Industriales , Microalgas/metabolismo , Biomasa , Reactores Biológicos , Dióxido de Carbono/metabolismo , Chlorella/crecimiento & desarrollo , Contaminación Ambiental/prevención & control , Esterificación , Calentamiento Global/prevención & control , Metabolismo de los Lípidos , Microalgas/crecimiento & desarrollo , Centrales EléctricasRESUMEN
Fas-mediated caspase-dependent cell apoptosis has been well investigated. However, recent studies have shown that Fas can induce nonapoptotic caspase-independent cell death (CICD) when caspase activity is inhibited. Currently, the molecular mechanism of this alternative cell death mediated by Fas remains unclear. In this study, we investigated the signaling pathway of Fas-induced CICD in mouse embryonic fibroblasts (MEFs) whose caspase function was disrupted by the pan-caspase inhibitor Z-VAD-FMK and its coupling to inflammatory responses. Our results revealed that receptor-interacting protein 1 and tumor necrosis factor receptor-associated factor 2 play important roles in FasL-induced CICD. This death is associated with intracellular reactive oxygen species (ROS) production from mitochondria, as a ROS scavenger (BHA), antioxidants (trolox, NAC), and a mitochondrial respiratory chain uncoupler (rotenone) could prevent this event. Furthermore, delayed and sustained JNK activation, mitochondrial membrane potential breakdown, and loss of intracellular GSH were observed. In addition to CICD, FasL also induces cyclooxygenase-2 and MIP-2 gene upregulation, and both responses are attributed to ROS-dependent JNK activation. Taken together, these results demonstrate alternative signaling pathways of Fas upon caspase inhibition in MEFs that are unrelated to the classical apoptotic pathway, but steer cells toward necrosis and an inflammatory response through ROS production.
Asunto(s)
Ciclooxigenasa 2/metabolismo , Proteína Ligando Fas/metabolismo , Fibroblastos/fisiología , Mitocondrias/fisiología , Clorometilcetonas de Aminoácidos/farmacología , Animales , Apoptosis , Inhibidores de Caspasas , Caspasas/fisiología , Línea Celular , Quimiocina CXCL2/genética , Quimiocina CXCL2/metabolismo , Cromanos/farmacología , Ciclooxigenasa 2/genética , Fibroblastos/patología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Inflamación , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Potencial de la Membrana Mitocondrial/fisiología , Ratones , Especies Reactivas de Oxígeno , Transducción de Señal , Receptor fasRESUMEN
Death receptor-mediated tumor cell death, either alone or in combination with other anticancer drugs, is considered as a new strategy for anticancer therapy. In this study, we have investigated the effects and molecular mechanisms of 5-aminoimidazole-4-carboxamide riboside [AICAR; a pharmacologic activator of AMP-activated protein kinase (AMPK)] in sensitizing tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)- and TNFalpha-induced apoptosis of human colon cancer HCT116 cells. The cytotoxic action of AICAR requires AMPK activation and may occur at various stages of apoptotic pathways. AICAR cotreatment with either TRAIL or TNFalpha enhances activities of caspase-8, caspase-9, and caspase-3; down-regulates the antiapoptotic protein Bcl-2; increases the cleavage of Bid and results in the decrease of mitochondrial membrane potential; potentiates activation of p38 and c-Jun NH(2)-terminal kinase; and inhibits nuclear factor-kappaB activity. In addition, this sensitized cell apoptosis was neither observed in p53-null HCT116 cells nor affected by the cotreatment with mevalonate. In summary, we have developed a novel strategy of combining AICAR with TRAIL for the treatment of colon cancer cells. The sensitization effect of AICAR in cell apoptosis was mediated through AMPK pathway, requires p53 activity, and involves mitochondria-dependent apoptotic cascades, p38 and c-Jun NH(2)-terminal kinase.