Enhancing biohydrogen production from xylose through natural FeS2 ore: Mechanistic insights.

In this study, we investigated the advantages of utilizing natural FeS2 ore in the context of dark fermentative hydrogen production within a fermentation system employing heat-treated anaerobic granular sludge with xylose as the carbon source. The results demonstrated a significant improvement in both hydrogen production and the maximum rate, with increases of 2.58 and 4.2 times, respectively. Moreover, the presence of FeS2 ore led to a reduction in lag time by more than 2-3 h. The enhanced biohydrogen production performance was attributed to factors such as the intracellular NADH/NAD+ ratio, redox-active components of extracellular polymeric substances, secreted flavins, as well as the presence of hydrogenase and nitrogenase. Furthermore, the FeS2 ore served as a direct electron donor and acceptor during biohydrogen production. This study shed light on the underlying mechanisms contributing to the improved performance of biohydrogen production from xylose during dark fermentation through the supplementation of natural FeS2 ore.

Performance and mechanism of different pretreatment methods for inoculated sludge in biohydrogen production.

A comparison was conducted between pre-culture bacteria (PCB) and heat treatment anaerobic granular sludge (HTAGS) for hydrogen production, and it was found that hydrogen molar yield (HMY) of PCB was 21-35% higher than that of HTAGS. The addition of biochar increased hydrogen production in both cultivation methods by acting as an electron shuttle to enhance extracellular electron transfers of Clostridium and Enterobacter. On the other hand, Fe3O4 did not promote hydrogen production in PCB experiments but had a positive effect on HTAGS experiments. This was due to the fact that PCB was mainly composed of Clostridium butyricum, which could not reduce extracellular iron oxide, resulting in a lack of respiratory driving force. In contrast, HTAGS retained a significant amount of Enterobacter, which possess the ability of extracellular anaerobic respiration. Different pretreatment methods of inoculum resulted in significant changes in the sludge community, thus exerting a noticeable impact on biohydrogen production.

Responses of Bacillus sp. under Cu(II) stress in relation to extracellular polymeric substances and functional gene expression level.

The production and composition of extracellular polymeric substances (EPS), as well as the EPS-related functional resistance genes and metabolic levels of Bacillus sp. under Cu(II) stress, were investigated. EPS production increased by 2.73 ± 0.29 times compared to the control when the strain was treated with 30 mg L-1 Cu(II). Specifically, the polysaccharide (PS) content in EPS increased by 2.26 ± 0.28 g CDW-1 and the PN/PS (protein/polysaccharide) ratio value increased by 3.18 ± 0.33 times under 30 mg L-1 Cu(II) compared to the control. The increased EPS secretion and higher PN/PS ratio in EPS strengthened the cells' ability to resist the toxic effect of Cu(II). Differential expression of functional genes under Cu(II) stress was revealed by Gene Ontology pathway enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The enriched genes were most obviously upregulated in the UMP biosynthesis pathway, the pyrimidine metabolism pathway, and the TCS metabolism pathway. This indicates an enhancement of EPS regulation-related metabolic levels and their role as a defense mechanism for cells to adapt to Cu(II) stress. Additionally, seven copper resistance genes were upregulated while three were downregulated. The upregulated genes were related to the heavy metal resistance, while downregulated genes were related to cell differentiation, indicating that the strain had initiated an obvious resistance to Cu(II) despite its severe cell toxicity. These results provided a basis for promoting EPS-regulated associated functional genes and the application of gene-regulated bacteria in heavy metal-containing wastewater treatment.

The acceleration on decolorization of azo dyes by magnetic lignin-based materials via enhancing the extracellular electron transfer.

Two novel and eco-friendly redox mediators (RMs), magnetic oxidative vanillin (MOV) and magnetic oxidative syringaldehyde (MOS), both derived from lignin, were prepared to improve the decolorization of the methyl orange (MO) dye. The Decolorization Efficiency (DE) of MO in the batch experiments with MOV and MOS were increased by more than 60% and 22%, respectively, when compared to the control experiment without magnetic RMs. Moreover, the two magnetic RMs could maintain stable DE of MO in sequenced batch reactors (SBRs), and negligible leaching of the oxidized lignin monomers was observed under various environmental conditions. Density Function Theory (DFT) calculations were used to propose three potential biodegradation mechanisms for azo dyes, and the key intermediates were confirmed using high-performance liquid chromatography. This study proposed a feasible strategy for functional utilization of lignin resource, as well as a practical method for effectively treating azo dye-containing wastewater.

Characteristics and comparisons of the aerobic and anaerobic denitrification of a Klebsiella oxytoca strain: Performance, electron transfer pathway, and mechanism.

The performance and electron (e-) transfer mechanisms of anaerobic and aerobic denitrification by strain Klebsiella were investigated in this study. The RT-PCR results demonstrated that the membrane bound nitrate reductase gene (narG) and Cu-nitrite reductase gene (nirK) were responsible for both aerobic and anerobic denitrification. The extreme low gene relative abundance of nirK might be responsible for the severe accumulation of NO2--N (nitrogen in the form of NO2- ion) under anaerobic condition. Moreover, the nitrite reductase (Nir) activity was 0.31 µg NO2--N min-1 mg-1 protein under anaerobic conditions, which was lower than that under aerobic conditions (0.38 µg NO2--N min-1 mg-1 protein). By using respiration chain inhibitors, the e- transfer pathways of anaerobic and aerobic denitrification of Klebsiella strain were constructed. Fe-S protein and Complex III were the core components under anaerobic conditions, while Coenzyme Q (CoQ), Complexes I and III played a key role in aerobic denitrification. Nitrogen assimilation was found to be the main way to generate NH4+-N (nitrogen in the form of NH4+ ion) during anaerobic denitrification, and also served as the primary nitrogen removal way under aerobic condition. The results of this study may help to improve the understanding of the core components of strain Klebsiella during aerobic and anaerobic denitrifications, and may suggest potential applications of the strain for nitrogen-containing wastewater.

Phytochemical Delivery Through Transferosome (Phytosome): An Advanced Transdermal Drug Delivery for Complementary Medicines.

Transdermal drug delivery aims to create a safe and effective method of administering drugs through the skin that attracts a lot of attention and investment due to the constant progress in the field. Transferosomes are flexible or malleable vesicles (having almost the same structure as liposomes but with better skin penetration properties) discovered initially in the early 90s. The name transferosomes, which means "carrying bodies," is coined from the Latin phrase "Transferee," which means "to carry through," and the Greek term "soma," meaning "body." In comparison to typical herbal extracts, phytosomes (Transferosomes) are created by attaching specific herbal extracts to phosphatidylcholine, resulting in a formulation with increased solubility and, hence, better absorption, resulting in improved pharmacokinetic and pharmacodynamic features of the entrapped drugs. We are using the word phytosomes and transferosomes interchangeably as we have consolidated vesicular delivery of herbal drugs through skin. In this mini-review, we have demonstrated the enormous potential of developing nanotechnology to deliver bioactive phytochemicals, with a special emphasis on phytosomes (Transferosomes) as a unique lipid-based nanocarrier for transdermal drug delivery.

Acceleration of the bio-reduction of methyl orange by a magnetic and extracellular polymeric substance nanocomposite.

Extracellular electron transfer (EET) plays an important role in bio-reduction of environmental pollutants. Extracellular polymeric substances (EPS), a kind of biogenic macromolecule, contain functional groups responsible for acceleration of EET. In this study, azo dye-methyl orange (MO) was chosen as a model pollutant, and a Fe3O4 and EPS nanocomposite (Fe3O4@EPS) was prepared to evaluate its promotion on the bio-reduction of MO. The flower-like core-shell configuration of Fe3O4@EPS with a 12 nm of light layer of EPS was confirmed by TEM. The redox ability of EPS was well reserved on Fe3O4@EPS by FTIR and electrochemical test. The application of Fe3O4@EPS on sustained acceleration of MO decolorization were confirmed by batch experiments and anaerobic sequenced batch reactors. Due to biocompatibility of the biogenic shell, the as-prepared Fe3O4@EPS exhibited low toxic to microorganisms by the Live/dead cell test. Moreover, negligible leaching of EPS under high concentration of various anions and less than 10% of EPS was released under extreme acidic and basic pH condition. The results of study provided a new preparation method of biological intimate and environmentally friendly redox mediators and suggested a feasible way for its use on bio-reduction of pollutants.

The role of anthraquinone-2-sulfonate on biohydrogen production by Klebsiella strain and mixed culture.

The role of anthraquinone-2-sulfonate (AQS) on biohydrogen production was explored in this study. The hydrogen molar yield (HMY) of the batch experiment with 0.2 mM AQS was not significantly improved comparing to that without AQS, but the acetate and ethanol yields were increased by 12.1% and 9.82%, respectively. According to the metabolites flux analysis, e- balance calculations and stoichiometry results, the biogenic anthrahydroquinone-2,6,-disulfonate (AH2QS) preferred to improve the H2 generation that catalyzed by hydrogenase, but not likely affect the H2 generation that through formate cleavage pathway (FCP). However, comparing to the mix culture without AQS, the hydrogen production rate and hydrogen yield were increased by 20.97% of 1.96%, respectively, in the presence of AQS. The results of this study provided better understanding of the role of AQS on biohydrogen production by the strain that follows FCP, and the synergistic biohydrogen production by the co-culture that follows FCP and butyrate/acetate pathway.

Adsorption characteristics of methylene blue by a dye-degrading and extracellular polymeric substance -producing strain.

Biosorption of dye by microbes and the extracellular polymeric substances (EPS) were of great environmental significance, especially for the dye-degrading and EPS-producing strain. Previous studies were mainly focused on the adsorption capacities and regeneration properties of pure culture, few were on the biosorption of dyes by the dye-degraders and the contributions of EPS on adsorption. In this study, a dye-degrading and EPS-producing strain i.e., Klebsiella oxytoca was used to evaluate its removal capacity to methylene blue. The maximum adsorption capacity (qe) by the strain was calculated as 145 mg g-1, which is superior to many reported bio-adsorbents and some synthetic materials. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results suggested that CO, -NH2 and P-OH groups were involved in the adsorption. High pressure steam sterilization (HPSS) increased the hydrophilicity of cell wall but did not significantly change the cell structure. Compared with the dead resting cell (DRC), the relative higher qe obtained by live resting cell (LRC) possibly due to the loss of some cell structure during the HPSS process. Adsorption experiments by EPS-free LRC, confocal laser microscope and three-dimensional excitation-emission matrix fluorescence spectroscopy results confirmed that the EPS played a role in the adsorption of MB dye. The adsorption characteristics of the dye-degrader and the contributions of EPS on adsorption were investigated in detail in this study. The results were benefit for better understanding of the interaction mechanisms between the dye molecules and cells that before the biodegradation process, which were of great significance for the practical usage of residual sludge on removal of dyes.

Energy-saving preparation of a bioflocculant under high-salt condition by using strain Bacillus sp. and the interaction mechanism towards heavy metals.

A highly efficient bioflocculant, i.e., Na-Bsp was successfully prepared by using a tolerant strain-Bacillus sp. under high-salt condition without sterilization. Salt-containing medium was not infected by other strains throughout the whole incubation period in 168 h. The as-prepared Na-Bsp was found to be cation-dependent, exhibiting high flocculant efficiency (FE) i.e., 97.69 ± 0.61%, towards kaolin particles by aid of Fe3+. High FE values were well maintained under a wide pH range and/or boiled water treatment, likely because of the main constituent of polysaccharide. The presence of hydroxyl, carboxyl, and amine groups on the bioflocculant surface were possibly responsible for strong interactions with heavy metals. The adsorption capacities of Pb2+, Cu2+ and Cr6+ were 1000.0, 434.8 and 384.6 mg g-1, respectively. The changing of structure and configuration of bioflocculant during the metal adsorption were explored by the scanning electron microscope with electron energy loss spectroscopy and three-dimensional excitation-emission fluorescence spectrometry. This study provided a novel production method, whereby the conventional sterilization could be avoided, which is of great environmental significance for steam-saving. Furthermore, the as-prepared Na-Bsp exhibited high adsorption capacities toward heavy metals, which sheds lights on its potential usage as an alternative adsorbent.

Preparation of a bioflocculant by using acetonitrile as sole nitrogen source and its application in heavy metals removal.

A novel bioflocculant, A-GS408, produced by Klebsiella oxytoca GS-4-08 cultured in acetonitrile (ACN) as sole nitrogen source was investigated in this study. A complete degradation of 1 g l-1 of ACN was achieved in 350 h, and 4.6 g of crude A-GS408 can be obtained in one litter of synthetic medium. The as-prepared bioflocculant exhibits good flocculation efficiency (over 90%) toward Kaolin solution with the aid of Fe3+. Chemical analysis showed that the bioflocculant was mainly composed of polysaccharides (46.3%) and proteins (20.6%). FTIR and XPS results indicated the abundant carboxyl, amine and hydroxyl groups in A-GS408 s, which play an important role on Pd2+ and Cu2+ adsorption. The adsorption of heavy metals can be well stimulated by Freundlich isotherm equation, and the Kf was up to 439.2 mg1-1/n l1/n g-1 and 112.2 mg1-1/n l1/n g-1 for Pb2+ and Cu2+, respectively. The kinetic fitting results proved that the adsorption of heavy metals by A-GS408 was chemisorption. This study may provide a new method for preparation of bioflocculant, which can not only degrade toxic compound i.e., acetonitrile, but also can reuse considerable nitrogen source from nitrile-containing wastewater.

A novel Fe(III) dependent bioflocculant from Klebsiella oxytoca GS-4-08: culture conditions optimization and flocculation mechanism.

In this work, the effect of cultivation factors on the flocculation efficiency (FE) of bioflocculant P-GS408 from Klebsiella oxytoca was optimized by the response surface methodology. The most significant factor, i.e. culture time, was determined by gray relational analysis. A total of 240 mg of purified P-GS408 was prepared from 1 liter of culture solution under the optimal conditions. GC-MS analysis results indicated that the polysaccharide of P-GS408 mainly contains Rhamnose and Galactose, and the existence of abundant hydroxyl, carboxyl and amino groups was evidenced by FTIR and XPS analyses. With the aid of Fe3+, the FE of kaolin solution by P-GS408 could achieve 99.48% in ten minutes. Functional groups of polysaccharide were involved in the first adsorption step and the zeta potential of kaolin solution changed from -39.0 mV to 43.4 mV in the presence of Fe3+ and P-GS408. Three-dimensional excitation-emission (EEM) fluorescence spectra demonstrates that the trivalent Fe3+ and Al3+ can bind efficiently with P-GS408, while those univalent and divalent cations cannot. With the help of SEM images, FTIR, zeta potential and EEM spectra, we proposed the P-GS408 flocculation mechanism, which consists of coordination bond combination, charge neutrality, adsorption and bridging, and net catching.

Betatrophin Acts as a Diagnostic Biomarker in Type 2 Diabetes Mellitus and Is Negatively Associated with HDL-Cholesterol.

Objective. By assessing its circulating concentrations in type 2 diabetes mellitus (T2DM) patients, we aimed to explore the associations of betatrophin with various metabolic parameters and evaluate its diagnostic value in T2DM. Methods. A total of 58 non-diabetes-mellitus (NDM) subjects and 73 age- and sex-matched newly diagnosed T2DM patients were enrolled. Correlation analyses between circulating betatrophin levels and multiple metabolic parameters were performed. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value of betatrophin concentration in T2DM. Results. Circulating betatrophin levels were approximately 1.8 times higher in T2DM patients than in NDM individuals (median 747.12 versus 407.41 pg/mL, P < 0.001). Correlation analysis showed that betatrophin was negatively associated with high-density lipoprotein cholesterol (HDL-C) levels in all subjects. ROC curve analysis identified betatrophin as a potent diagnostic biomarker for T2DM. The optimal cut-off point of betatrophin concentration for predicting T2DM was 501.23 pg/mL. Conclusions. Serum betatrophin levels were markedly increased in newly diagnosed T2DM patients and further elevated in obese T2DM subjects. Betatrophin was negatively correlated with HDL-C levels. Our findings indicate that betatrophin could be a potent diagnostic biomarker for T2DM.

The performance of a diabetic retinopathy risk score for screening for diabetic retinopathy in Chinese overweight/obese patients with type 2 diabetes mellitus.

INTRODUCTION: Diabetic retinopathy (DR) is a common chronic microvascular diabetic complication. The presence of DR may indicate microcirculatory dysfunction in other organ systems besides visual morbidity. The objective of this study was to develop a simple diabetic retinopathy risk score to identify DR in Chinese overweight/obese patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS: A multicentre hospital-based cross-sectional study was carried out in Guangdong Province between August 2011 and March 2012. The evaluated 2699 patients included 1263 males and 1436 females, with an average age of 59.4 ± 13.0 years. RESULTS: The diabetic retinopathy risk score was conducted by age, duration of DM, history of antihypertensive drug treatment, and waist circumference. The area under the receiver operating characteristics curve for DR was 0.700 (95% CI 0.671-0.729). Comparing Youden's index of different values, the optimal cut-off point was 20 to predict DR. The odds ratio for one unit increase in the diabetic retinopathy risk score associated with the risk of DR was 1.104 (95% CI 1.089-1.120). CONCLUSIONS: Our data suggest that the diabetic retinopathy risk score could be a reliable primary screening tool for the presence of DR in Chinese overweight/obese patients with T2DM.

Investigation of single nucleotide polymorphisms based on the intronic sequences of the propylene alcohol dehydrogenase gene in Chinese tobacco genotypes.

A pair of primers was designed to amplify the propylene alcohol dehydrogenase gene sequence based on the cDNA sequence of the tobacco allyl-alcohol dehydrogenase gene. All introns were sequenced using traditional polymerase chain reaction (PCR) methods and T-A cloning. The sequences from common tobacco (Nicotiana tabaccum L.) and rustica tobacco (Nicotiana rustica L.) were analysed between the third intron and the fourth intron of the propylene alcohol dehydrogenase gene. The results showed that the alcohol dehydrogenase gene is a low-copy nuclear gene. The intron sequences have a combination of single nucleotide polymorphisms and length polymorphisms between common tobacco and rustica tobacco, which are suitable to identify the different germplasms. Furthermore, there are some single nucleotide polymorphism sites in the target sequence within common tobacco that can be used to distinguish intraspecific varieties.

Folic acid attenuates cognitive dysfunction in streptozotocin-induced diabetic rats.

Diabetic cognitive dysfunction is common in patients with diabetes but its pathogenesis is not clear. The aim of the present study is to investigate the role of 5', 10' methylene tetrahydrofolate reductase (MTHFR) in the development of diabetic cognitive impairment and test whether folic acid (FA) supplementation prevents cognitive dysfunction in diabetic rats. In the current study, three months after streptozotocin-induced diabetes onset, rats showed cognitive dysfunction including the prolonged escape latency, the decreased time spent in the target quadrant and the declined number of crossing the platform in Morris water maze test. Diabetic rats also presented elevated plasma homocysteine level and downregulation of MTHFR in hippocampus revealed by Western blotting. The diabetic cognitive dysfunction was attenuated by 30-day dietary FA treatment with a significantly decreased homocysteine level. In conclusion, these results suggest that MTHFR plays a crucial role in diabetic cognitive dysfunction and folate fortification might become a potent therapeutic strategy against diabetic cognitive impairment.

[Prevalence and risk factors for dyslipidemia in diabetics with overweight or obesity].

OBJECTIVE: To explore the prevalence and risk factors for dyslipidemia in diabetics with overweight or obesity. METHODS: Diabetics with overweight or obesity were recruited from 62 tertiary and secondary hospitals in Guangdong Province between August 2011 and March 2012. Dyslipidemia was diagnosed as total cholesterol (TC) ≥ 5.7 mmol/L or triglycerides (TG) ≥ 1.7 mmol/L or low-density-lipoprotein cholesterol (LDL-C) ≥ 3.6 mmol/L or high-density-lipoprotein cholesterol (HDL-C) < 1.29 mmol/L in females or HDL-C < 1.03 mmol/L in males. Binary Logistic regression was used to assess the associations between dyslipidemia and associated risk factors. RESULTS: Dyslipidemia was detected in 3160/3593 (87.9%) diabetics with overweight or obesity. And the prevalence of hypertriglyceridemia, low blood HDL-C, hypercholesterolemia and high blood LDL-C was 52.5% (1888/3593) , 54.1% (1945/3593), 33.1% (1188/3593) and 27.4% (985/3593) respectively. Among those with dyslipidemia, patients with simple and mixed dyslipidemia accounted for 34.1% and 53.9% respectively. In binary Logistic regression analysis, the presence of dyslipidemia were associated with female gender (OR = 1.593, 95%CI 1.233-2.057), hemoglobinA1c(HbA1c) (OR = 1.120, 95%CI 1.054-1.191), body mass index (OR = 1.084, 95%CI 1.022-1.150), hypertension (OR = 1.331, 95%CI 1.033-1.714), history of diabetes (OR = 1.586, 95%CI 1.186-2.120) and hyperuricacidemia (OR = 2.270, 95%CI 1.642-3.138). CONCLUSIONS: The prevalence of dyslipidemia is quite high in diabetics with overweight or obesity. The controls of blood pressure, serum uric acid level, blood glucose and body weight may reduce the prevalence of dyslipidemia, prevent and delay the development of cardiovascular complications and reduce the mortality of diabetics with overweight or obesity.

Prevalence and determinants of hyperuricemia in type 2 diabetes mellitus patients with central obesity in Guangdong Province in China.

This study investigated the prevalence and determinants of hyperuricemia in Chinese type 2 diabetes mellitus (T2DM) patients with central obesity. A multicentric hospital-based cross-sectional study was carried out in Guangdong Province between August 2011 and March 2012. At each hospital, Chinese T2DM patients with central obesity who were aged over 20 years, whose serum uric acid levels were measured, and who had lived in Guangdong Province for >=1 year, were recruited. Hyperuricemia was defined as serum uric acid >420 µmol/L in men and >360 µmol/L in women. Binary logistic regression was used to assess associated risk factors for hyperu-ricemia. A total of 2,917 T2DM patients with central obesity took part. The overall prevalence of hyperuricemia was 32.6% (36.1% for women, 28.4% for men). Binary logistic regression analyses demonstrated that women (OR: 1.576; 95% confidence interval (CI): 1.231, 2.018), high BMI (OR: 1.228; 95% CI: 1.094, 1.379), waist cir-cumference (OR: 1.135; 95% CI: 1.009, 1.276), hypertension (OR: 1.603; 95% CI: 1.263, 2.035), high total cho-lesterol (OR: 1.133; 95% CI: 1.002, 1.281), triglycerides (OR: 1.134; 95% CI: 1.069, 1.203), low HDL-cholesterol (OR: 0.820; 95% CI: 0.677, 0.995) and low estimated glomerular filtration rate (OR: 0.840; 95% CI: 0.815, 0.866) were risk factors associated with hyperuricemia. Hyperuricemia is prevalent in Chinese T2DM patients with central obesity and is significantly positively associated with women, cardiovascular risk factors such as obesity, hypertension and dyslipidemia, and low eGFR.

[A cross-sectional survey of blood pressure control in overweight or obese type 2 diabetic patients in Guangdong province].

OBJECTIVE: To investigate the current situation and influential factors of blood pressure (BP) control in type 2 diabetic patients with overweight or obesity in Guangdong province. METHODS: From August 2011 to March 2012, type 2 diabetic patients with overweight or obesity were recruited from 60 hospitals in 20 cities of Guangdong province, and received standard questionnaires. The conditions of demographic data, clinical examinations, the most recent laboratory assessment, history of disease and drug therapy were recorded. RESULTS: A total of 4029 patients were collected with age of (58.9 ± 12.9) years, and body mass index (BMI) of (27.28 ± 2.76) kg/m². Among the participants, controlled BP was achieved in 23.8% patients. Multiple logistic regression analysis showed that older age, obesity, previous history of hypertension and inadequate glycemic control were the independent factors related to unsatisfactory blood pressure control rate. Among the patients with hypertension, 53.5% took 1 kind of antihypertensive drug, 32.5% took two, and 11.3% took three or more. CONCLUSIONS: Type 2 diabetic patients with overweight or obesity in Guangdong province have poor BP control. Thus, active lifestyle interventions and drug therapy as a comprehensive management way should be taken for the population so as to reduce their cardiovascular events.

Prevalence and risk factors for diabetic retinopathy in a high-risk Chinese population.

BACKGROUND: Lifestyle plays an important role in the development of diabetic retinopathy. The lifestyle in Guangzhou is different from other cities in China as the Cantonese prefer eating rice porridge, but not spicy foods. The objectives of this study were to investigate the prevalence and determinants of diabetic retinopathy in a high-risk population of Guangzhou. METHODS: Subjects (619 totals) aged over 45 years old, without known diabetes were recruited from five randomly selected Guangzhou communities in 2009-2010. All participants were invited to complete the Finnish Diabetes Risk Score (FINDRISC) questionnaire. Subjects with FINDRISC score ≥ 9 were included in the study, and underwent an investigation of demographic data, a standardized physical examination, ocular fundus examination, and laboratory analyses. The minimum criterion for diagnosis of diabetic retinopathy was the presence of at least one microaneurysm. RESULTS: Of 619 subjects, 208 eligible subjects (122 women) with FINDRISC score ≥ 9 were included in the study. The mean age was 69.2 ± 8.5 years. Diabetic retinopathy was detected in 31 subjects, and the prevalence of diabetic retinopathy in subjects with high risk for diabetes was 14.9%. In binary logistic regression analysis, risk factors associated with diabetic retinopathy were history of impaired glucose regulation [odds ratio (OR), 7.194; 95% confidence interval (CI): 1.083, 47.810], higher hemoglobin A1c (HbA1c; OR, 2.912; 95% CI: 1.009, 8.402), higher two-hour postprandial plasma glucose level (OR, 1.014; 95% CI: 1.003, 1.025), and presence of microalbuminuria (OR, 5.387; 95% CI: 1.255, 23.129). CONCLUSIONS: Diabetic retinopathy was prevalent in a high-risk Chinese population from Guangzhou. Histories of impaired glucose regulation and microalbuminuria were strong risk factors for diabetic retinopathy.