Organic acids are organic compounds that can be synthesized using biological systems. They often contain one or more low molecular weight acidic groups, such as carboxyl group and sulphonic group. Organic acids are widely used in food, agriculture, medicine, bio-based materials industry and other fields. Yeast has unique advantages of biosafety, strong stress resistance, wide substrate spectrum, convenient genetic transformation, and mature large-scale culture technology. Therefore, it is appealing to produce organic acids by yeast. However, challenges such as low concentration, many by-products and low fermentation efficiency still exist. With the development of yeast metabolic engineering and synthetic biology technology, rapid progress has been made in this field recently. Here we summarize the progress of biosynthesis of 11 organic acids by yeast. These organic acids include bulk carboxylic acids and high-value organic acids that can be produced naturally or heterologously. Finally, future prospects in this field were proposed.
Saccharomyces cerevisiae/metabolism* ; Organic Chemicals ; Carboxylic Acids/metabolism* ; Metabolic Engineering ; Fermentation ; Acids

Aromatic compounds are a class of organic compounds with benzene ring(s). Aromatic compounds are hardly decomposed due to its stable structure and can be accumulated in the food cycle, posing a great threat to the ecological environment and human health. Bacteria have a strong catabolic ability to degrade various refractory organic contaminants (e.g., polycyclic aromatic hydrocarbons, PAHs). The adsorption and transportation are prerequisites for the catabolism of aromatic compounds by bacteria. While remarkable progress has been made in understanding the metabolism of aromatic compounds in bacterial degraders, the systems responsible for the uptake and transport of aromatic compounds are poorly understood. Here we summarize the effect of cell-surface hydrophobicity, biofilm formation, and bacterial chemotaxis on the bacterial adsorption of aromatic compounds. Besides, the effects of outer membrane transport systems (such as FadL family, TonB-dependent receptors, and OmpW family), and inner membrane transport systems (such as major facilitator superfamily (MFS) transporter and ATP-binding cassette (ABC) transporter) involved in the membrane transport of these compounds are summarized. Moreover, the mechanism of transmembrane transport is also discussed. This review may serve as a reference for the prevention and remediation of aromatic pollutants.
Humans ; Adsorption ; Bacteria/metabolism* ; Organic Chemicals ; Biological Transport ; ATP-Binding Cassette Transporters ; Polycyclic Aromatic Hydrocarbons/metabolism*

OBJECTIVES: To study the correlation of the expression of Lipin1 in visceral adipose tissue and Lipin2 in liver tissue with hepatic fat content in rats with intrauterine growth retardation (IUGR). METHODS: Pregnant rats were given a low-protein (10% protein) diet during pregnancy to establish a model of IUGR in neonatal rats. The pregnant rats in the control group were given a normal-protein (21% protein) diet during pregnancy. The neonatal rats were weighed and liver tissue was collected on day 1 and at weeks 3, 8, and 12 after birth, and visceral adipose tissue was collected at weeks 3, 8, and 12 after birth. The 3.0T ¹H-magnetic resonance spectroscopy was used to measure hepatic fat content at weeks 3, 8, and 12 after birth. Real-time PCR was used to measure mRNA expression levels of Lipin2 in liver tissue and Lipin1 in visceral adipose tissue. Western blot was used to measure protein levels of Lipin2 in liver tissue and Lipin1 in visceral adipose tissue. A Pearson correlation analysis was performed to investigate the correlation of mRNA and protein expression of Lipin with hepatic fat content. RESULTS: The IUGR group had significantly higher mRNA and protein expression levels of Lipin1 in visceral adipose tissue than the control group at weeks 3, 8, and 12 after birth (P<0.05). Compared with the control group, the IUGR group had significantly lower mRNA and protein expression levels of Lipin2 in liver tissue on day 1 after birth and significantly higher mRNA and protein expression levels of Lipin2 at weeks 1, 3, 8, and 12 after birth (P<0.05). At week 3 after birth, there was no significant difference in hepatic fat content between the IUGR and control groups (P>0.05), while at weeks 8 and 12 after birth, the IUGR group had a significantly higher hepatic fat content than the control group (P<0.05). The protein and mRNA expression levels of Lipin1 were positively correlated with hepatic fat content (r=0.628 and 0.521 respectively; P<0.05), and the protein and mRNA expression levels of Lipin2 were also positively correlated with hepatic fat content (r=0.601 and 0.524 respectively; P<0.05). CONCLUSIONS Upregulation of the mRNA and protein expression levels of Lipin1 in visceral adipose tissue and Lipin2 in liver tissue can increase hepatic fat content in rats with IUGR and may be associated with obesity in adulthood.
Adult ; Animals ; Female ; Fetal Growth Retardation ; Gene Expression ; Humans ; Liver/metabolism* ; Organic Chemicals ; Pregnancy ; RNA, Messenger/metabolism* ; Rats

With the increasing occurrence of haze during the summer, the physicochemical characteristics and toxicity differences in PM_2.5 in different seasons are of great concern. Hangzhou is located in an area that has a subtropical monsoon climate where the humidity is very high during both the summer and winter. However, there are limited studies on the seasonal differences in PM_2.5 in these weather conditions. In this test, PM_2.5 samples were collected in the winter and summer, the morphology and chemical composition of PM_2.5 were analyzed, the toxicity of PM_2.5 to human bronchial cells BEAS-2B was compared, and the correlation between PM_2.5 toxicity and the chemical composition was discussed. The results showed that during both the winter and summer, the main compounds in the PM_2.5 samples were water-soluble ions, particularly SO₄^2-, NO₃^-, and NH₄⁺, followed by organic components, while heavy metals were present at lower levels. The higher the mass concentration of PM_2.5, the greater its impact on cell viability and ROS levels. However, when the mass concentration of PM_2.5 was similar, the water extraction from the summer samples showed a greater impact on BEAS-2B than that from the winter samples. The cytotoxicity of PM_2.5 was closely associated with heavy metals and organic pollutants but less related to water-soluble ions.
Air Pollutants/toxicity* ; Bronchi/metabolism* ; Carbon/chemistry* ; Environmental Monitoring ; Humans ; Ions ; Metals, Heavy ; Organic Chemicals ; Particle Size ; Particulate Matter/toxicity* ; Seasons ; Temperature ; Water

OBJECTIVETo study the effects of LIF combined with bFGF on the proliferation, stemness and senescence of hUC-MSC.

METHODSExperiments were divided into 4 groups: control group, in which the cells were treated with complete medium (α-MEM containing 10% FBS); group LIF, in which the cells were treated with complete medium containing 10 ng/ml LIF; group bFGF, in which the cells were treated with complete medium containing 10 ng/ml bFGF; combination group, in which the cells were treated with complete medium containing 10 ng/ml LIF and 10 ng/ml bFGF. The growth curves of hUC-MSC at passage 4 in different groups were assayed by cell counting kit 8. Cellular morphologic changes were observed under inverted phase contrast microscope; hUC-MSC senescence in different groups was detected by β-galactosidase staining. The expression of PCNA, P16, P21, P53, OCT4 and NANOG genes was detected by RT-PCR.

RESULTSThe cell growth curves of each group were similar to the S-shape; the cell proliferation rate from high to low as follows: that in the combination group > group bFGF > group LIF > control group. Senescence and declining of proliferation were observed at hUC-MSC very early in control group; the cells in group LIF maintained good cellular morphology at early stage, but cell proliferation was slow and late senescence was observed; a few cells in group bFGF presented signs of senescence, but with quick proliferation; the cells in combination group grew quickly and maintained cellular morphology of hUC-MSC for long time. The LIF and bFGF up-regulated the expression of PCNA, OCT4 and NANOG, while they down-regulated the expression of P16, P21, P53, and their combinative effects were more significant.

CONCLUSIONLIF combined with bFGF not only can promote the proliferation and maintenance of stemness of hUC-MSC, but also can delay the senescence of hUC-MSC.

Cell Cycle ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Fibroblast Growth Factor 2 ; pharmacology ; Genes, Homeobox ; Humans ; Leukemia Inhibitory Factor ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Octamer Transcription Factor-3 ; metabolism ; Organic Chemicals ; Proliferating Cell Nuclear Antigen ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; Umbilical Cord ; cytology

OBJECTIVETo investigate the effect of transforming growth factor-β1 (TGF-β1) on the differentiation of bone marrow-derived mesenchymal stem cells (MSCs) into cancer-associated fibroblasts(CAFs).

METHODSMSCs were cultured in α-MEM with recombinant human TGF-β1 or in tumor-conditioned medium.The expression of CAFs markers were detected by immunofluorescence and quantitative RT-PCR.

RESULTSThe qRT-PCR assay showed that the expression of CAFs markers FAP, ACTA, CAV, CCL5, CXCR4, FSP1, SDF-1 and vimentin were 9.92±2.16, 7.76±1.28, 3.04±0.95, 3.28±2.16, 2.13±0.71, 1.41±0.66, 2.25±0.86 and 1.38±0.56, respectively, significantly upregulated in the MSCs co-cultured with TGF-β1 or TCM. The relative levels of FAP, ACTA, CAV, CCL5, CXCR4, FSP1, SDF-1 and vimentin mRNA in the TCM group were 7.52±1.76, 5.02±1.18, 1.98±1.19, 1.82±1.19, 2.95±0.86, 1.44±0.67, 2.08±0.74 and 1.47±0.55, respectively, indicating that MSCs can express CAFs phenotype.TGF beta signaling pathway inhibitor SB-431542 could inhibit the differentiation. Both immunofluorescence and Western blot confirmed the above results.

CONCLUSIONSTGF-β1 induces differentiation of local MSCs to CAFs by upregulating the expression of pSmad3, so as to further promote the growth of cancer cells.

Benzamides ; pharmacology ; Bone Marrow Cells ; cytology ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Chemokine CXCL12 ; metabolism ; Coculture Techniques ; Culture Media, Conditioned ; Dioxoles ; pharmacology ; Fibroblasts ; cytology ; Humans ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Organic Chemicals ; Receptors, CXCR4 ; metabolism ; Recombinant Proteins ; pharmacology ; Smad3 Protein ; metabolism ; Transforming Growth Factor beta1 ; antagonists & inhibitors ; pharmacology ; Vimentin ; metabolism

Confronted with the gradual exhaustion of the earth's fossil energy resources and the grimmer environmental deterioration, the bio-based process to produce high-value added platform chemicals from renewable biomass is attracting growing interest. Escherichia coli has been chosen as a workhouse for the production of many valuable chemicals due to various advantages, such as clear genetic background, convenient to be genetically modified and good growth properties with low nutrient requirements. Rational strain development of E. coli achieved by metabolic engineering strategies has provided new processes for efficiently biotechnological production of various high-value chemical building blocks. This review focuses on recent progresses in metabolic engineering of E. coli that lead to efficient recombinant biocatalysts for production of high-value organic acids such as succinic acid, 3-hydroxypropanoic acid and glucaric acid as well as alcohols like glycerol and xylitol. Besides, this review also discusses several other platform chemicals, including 2,5-furan dicarboxylic acid, aspartic acid, glutamic acid, itaconic acid, levulinic acid, 3-hydroxy-gamma-butyrolactone and sorbitol, which have not been produced by E. coli until now.
Acids ; metabolism ; Alcohols ; metabolism ; Biocatalysis ; Escherichia coli ; genetics ; metabolism ; Industrial Microbiology ; methods ; Metabolic Engineering ; methods ; Metabolic Networks and Pathways ; genetics ; Organic Chemicals ; metabolism

Biobased chemicals are one of the main missions of bioeconomy. In this special issue, we reviewed the recent progress in the metabolic engineering and fermentation control study on biobased succinic acid, adipic acid, lactic acid, 3-hydroxypropanoic acid, glucaric acid, glycerol, xylitol, higher alcohols and ethylene, recombinant construction for the direct utilization of lignocelluloses, biotransformation of bio-based lactic acid, and salting-out extraction of bio-based chemicals. Some research articles on biobased succinic acid, D-mannitol, malic acid, 5-aminolevulinic acid, 1,3-propanediol, and butanol are also included.
Adipates ; metabolism ; Biotechnology ; methods ; Biotransformation ; Escherichia coli ; genetics ; metabolism ; Industrial Microbiology ; methods ; Lactic Acid ; metabolism ; Lignin ; metabolism ; Metabolic Engineering ; methods ; Organic Chemicals ; metabolism ; Saccharomyces cerevisiae ; genetics ; metabolism ; Succinic Acid ; metabolism

The traditional light microscopy has limitations for precise growth assays of malaria parasites in culture or for assessment of new compounds for antimalarial activity; the speed and high reproducibility of flow cytometry can overcome these limitations. A flow cytometric method using PicoGreen, a DNA-binding fluorochrome, was developed with optimal precision suitable for performing growth assays of low-parasitemia field isolates. In addition, intra- and inter-person reproducibility of the flow cytometric and the microscopic method were compared in order to quantitatively demonstrate the improved precision. RNase treatment contributed to the precision of the flow cytometric measurements by enhancing the signal-to-noise ratios. Coefficients of variation of the method were smaller than 10% for 0.1% or higher parasitemia samples. The intra- and inter-person coefficients of variation of the flow cytometric method were three to six times smaller than those of the microscopic method. The flow cytometric method developed in this study yielded substantially more precise results than the microscopic method, allowing determination of parasitemia levels of 0.1% or higher, with coefficients of variation smaller than 10%. Thus, the PicoGreen method could be a reliable high sensitivity assay for analysis of low parasitemia samples and might be applied to a high throughput system testing antimalarial drug activity.
*Flow Cytometry ; Fluorescent Dyes/chemistry ; Humans ; *Microscopy ; Organic Chemicals/chemistry ; Parasitemia/*diagnosis ; Plasmodium falciparum/*isolation & purification ; Reproducibility of Results ; Ribonucleases/metabolism ; Signal-To-Noise Ratio

To meet the needs of detection of infectious bursal disease virus (IBDV) under high efficient culture, a SYBR Green I real-time RT-PCR (qRT-PCR) was developed using a pair of primers specific to the conserved region of VP4 gene of IBDV and compared with TCID50 method by monitoring the proliferation dynamics of IBDV in DF-1 cell line adherent to micro carrier in tubular reactor. The results showed that the RT-PCRassay was linear in the range of 4. 03 X 10(1)-10(9) copies/microL. The IBDV RNA detection limit was 40 copies/microL, which was 1 000 times more sensitive than conventional PCR. No cross-reactions with other viruses was observed. The intra-assay coefficient of variation was less than 0.05%. There was a parallel correlation of IBDV proliferation dynamics in DF-1 cell under Micro carrier suspension and static adherent culture by the qRT-PCR assay and TCID50 method. The detection results of the IBDV samples from tubular and flask culture showed the differences of the micro carrier and adherent culture by both methods. In conclusion, the qRT-PCR assay is more rapid and sensitive than the TCID50 method, which is more appropriate for the real time detection of IBDV.
Animals ; Calibration ; Cell Line ; Conserved Sequence ; DNA Primers ; genetics ; Infectious bursal disease virus ; genetics ; isolation & purification ; Organic Chemicals ; chemistry ; metabolism ; Real-Time Polymerase Chain Reaction ; methods ; Reproducibility of Results ; Spectrometry, Fluorescence ; Viral Proteins ; genetics ; Virus Replication