Microalgal-bacterial consortia for efficient wastewater treatment: Optimization using response surface methodology.

The performance of microalgal-bacterial consortia in wastewater treatment and biomass production needs to be further optimized to meet increasingly stringent effluent standards and operating costs. Besides, due to uncontrollability of ambient conditions, it is generally believed that operating conditions (e.g., aeration) respond to ambient conditions (e.g., illumination). Therefore, response surface methodology (RSM) based on Box-Behnken design was used in this study to analyze the removal of chemical oxygen demand (COD), NH3 -N and TP, and algal biomass of the microalgal-bacterial consortia within 48 h. The results showed that under medium illumination intensity (5000 lx), photoperiod (12:12) and aeration rate (0.55 L min -1 ), the removal efficiency of COD, NH3 -N and TP was the highest, and the maximal biomass growth rates were 95.43%, 95.49%, 89.42% and 99.63%, respectively. However, as the limited critical removal requirements of TP, the effluent standards can only be achieved within the small illumination intensity and photoperiod available range, even under medium aeration conditions, which means that under fixed operating conditions, the effective operation range will be very limited. In addition, based on RSM and differential equation analysis, the further study indicated that the effective treatment range can be greatly expanded within aeration responding, which meets the discharge standard of pollutants in China. PRACTITIONER POINTS: Illumination was responded by aeration for optimizing performance of microalgal-bacterial consortium for wastewater treatment and biomass productivity. The strategy of optimization was based on response surface methodology. The maximum effect on wastewater treatment and biomass productivity was based on partial differential equations and quadratic inhomogeneous equations. Limited to critical TP-removal requirements, effluent standards can meet only in the small-usable range of illumination, under medium aeration.

Older Adults' Access to and Satisfaction With Primary Hospitals Based on Spatial and Non-spatial Analyses.

In order to improve the health and quality of life of older adults, the Chinese government is dedicated to establishing an equilibrium level of primary healthcare services for all communities. However, little attention has been paid to measuring the accessibility of primary hospitals to older adults, nor to understanding the seniors' satisfaction with and needs for primary healthcare services. Therefore, this study sought to investigate the spatial accessibility of primary hospitals to older adults, and also to examine the impact of walking distances on the seniors' satisfaction with their healthcare services. A two-step floating catchment area method was applied to measure the spatial accessibility of primary hospitals to older adults at the level of subdistricts. In order to investigate the actual opinions of older adults and verify the results of spatial analysis, a large-scale questionnaire survey was also conducted. The analyses found that (1) primary hospitals were not equally distributed; (2) most older adults did not have access to primary hospitals within a threshold walking distance of 1,000 m, but they usually could reach a hospital in their subdistrict within a threshold distance of 2,000 m; (3) older adults' satisfaction levels with primary hospitals were significantly different among subdistricts; (4) long walking distances negatively influenced older adults' satisfaction with primary hospitals; (5) the satisfaction of older adults was highest with a threshold distance of 500 m; and (6) a piecewise regression model indicated that older adults' satisfaction with primary hospitals would decrease with an increase in walking distance to the hospital. When the walking distances exceeded 1,000 m, the slope of the linear regression model increased significantly compared with the slope for walking distances less than 1,000 m. By adopting multiple research methods and capturing older adults' behaviors and satisfaction, our results provide (1) data on the importance of accessibility of primary hospitals to older adults, and (2) insights for future planning to achieve equity in primary healthcare and enhance the spatial distribution of primary hospitals.

Convergent community structure of algal-bacterial consortia and its effects on advanced wastewater treatment and biomass production.

Microalgal-bacterial consortium is an effective way to meet increasingly stringent standards in wastewater treatment. However, the mechanism of wastewater removal effect has not been properly explained in community structure by phycosphere. And little is known about that the concept of macroecology was introduced into phycosphere to explain the phenomenon. In the study, the algal-bacterial consortia with different ratios of algae and sludge were cultured in same aerobic wastewater within 48 h in photobioreactors (PSBRs). Community structure at start and end was texted by metagenomic analysis. Bray-Curtis similarities analysis based on microbial community showed that there was obvious convergent succession in all consortia, which is well known as "convergence" in macroecology. The result showed that Bray-Curtis similarities at End (overall above 0.88) were higher than these at Start (almost less than 0.66). In terms of community structure, the consortium with 5:1 ratio at Start are the more similar with the consortia at End by which the maximum removal of total dissolved nitrogen (TDN, 73.69%), total dissolved phosphorus (TDP, 94.40%) and NH3-N (93.26%) in wastewater treatment process and biomass production (98.2%) higher than other consortia, according with climax community in macroecology with the highest resource utilization than other communities. Therefore, the macroecology can be introduced into phycosphere to explain the consortium for advanced wastewater treatment and optimization community structure. And the study revealed a novel insight into treatment effect and community structure of algal-bacterial consortia for advanced wastewater treatment, a new idea for to shortening the culture time of consortium and optimize predicting their ecological community structure and predicting ecological community.

Do Age-Friendly Rural Communities Affect Quality of Life? A Comparison of Perceptions from Middle-Aged and Older Adults in China.

The aging population in rural areas of China faces serious challenges due to urban-rural disparities. In order to improve the active aging of rural older adults, the establishment of age-friendly communities is encouraged. However, globally, the focus is on age-friendly communities in urban areas, not reflecting rural communities. Hence, we addressed the importance of age-friendly rural communities (AFRCs) and aimed to investigate their impact on the quality of life (QoL) of older adults. We examined different perceptions of AFRCs among older adults (aged over 60) and middle-aged people (45-60) in rural communities with questionnaire surveys (n = 470 and 393, respectively). Several statistical methods, such as Chi-squared test, t-test, reliability test, and multiple regression, were adopted to investigate and compare the perceptions of these two. The results indicated that (1) middle-aged people were more satisfied with AFRC components and had a higher QoL than older adults; (2) the QoL of middle-aged people was predicted by housing, accessibility, and outdoor spaces; (3) the QoL of older adults was affected by housing, outdoor spaces, social participation, and public transportation. These findings aid in our understanding of rural communities and the QoL of rural residents. They are helpful for urban planners and policymakers to improve the planning of AFRCs and supplement research on age-friendly communities in rural areas. Practical implementations are proposed for the planning of AFRCs, such as the passive design of residential housing, grouping of community facilities together, and improvement in the hygiene of outdoor spaces in rural areas.

Use of ultrasound for aiding lipid extraction and biodiesel production of microalgae harvested by chitosan.

In this work, chitosan, a biodegradable flocculant, was investigated to determine its utility in flocculating microalgae, its effect on cell integrity, and its impact on lipid extraction and the conversion to fatty acid methyl ester (FAME). Results showed that chitosan adequately performed flocculation on Chlorella vulgaris microalgae and achieved a high harvesting efficiency of 96.35 ± 1.96% when implemented under the following conditions: chitosan dose = 120 mg/L-1, pH = 5, mixing speed = 150 rpm for 20 min, followed by 10 min of settling time. Moreover, scanning electron microscope (SEM) combined with transmission electron microscope (TEM) demonstrated that chitosan protected the cells' structure from morphological damage. Finally, the highest lipid extraction yield and biodiesel production was obtained from the chitosan-harvested biomass when the microalgae were pretreated with ultrasound.

Advances in the use of microalgal-bacterial consortia for wastewater treatment: Community structures, interactions, economic resource reclamation, and study techniques.

The rise in living standards has generated a demand for higher aquatic environmental quality. The microalgal community and the surrounding organic molecules, environmental factors, and microorganisms, such as bacteria, are together defined as the phycosphere. The bacteria in the phycosphere can form consortia with microalgae through various forms of interaction. The study of the species in these consortia and their relative proportions is of great significance in determining the species and strains of stable algae that can be used in sewage treatment. This article summarizes the following topics: the interactions between microalgae and bacteria that are required to establish consortia; how symbiosis between algae and bacteria is established; microalgal competition with bacteria through inhibition and anti-inhibition strategies; the influence of environmental factors on microalgal-bacterial aggregates, such as illumination conditions, pH, dissolved oxygen, temperature, and nutrient levels; the application of algal-bacterial aggregates to enhance biomass production and nutrient reuse; and techniques for studying the community structure and interactions of algal-bacterial consortia, such as microscopy, flow cytometry, and omics. PRACTITIONER POINTS: Community structures in microalgal-bacterial consortia in wastewater treatment. Interactions between algae and bacteria in wastewater treatment. Effects of ecological factors on the algal-bacterial community in wastewater treatment. Economically recycling resources from algal-bacterial consortia based on wastewater. Technologies for studying microalgal-bacterial consortia in wastewater treatment.

Characterization and optimization of endogenous lipid accumulation in Chlorella vulgaris SDEC-3M ability to rapidly accumulate lipid for reversing nightly lipid loss.

BACKGROUND: During inevitable light/dark cycle, lipid productivity of outdoor microalgae photoautotrophic cultivation is lowered by nightly biomass and lipid loss. To minimize, or even reverse the nightly lipid loss, it was expected that lipid accumulation would not cease, even if at night. Without relying on photosynthesis and organic matter in media, endogenous lipid accumulation that consumes energy and carbon sources derived from cells themselves, namely endogenous accumulation, is the only way for lipid production. The main aims of the present study was to characteristic endogenously accumulated lipid, confirm feasibility to reverse nightly lipid loss, and determine optimal conditions and its quality suitability for biodiesel feedstock production under stress conditions. RESULTS: Chlorella vulgaris SDEC-3M ability to rapidly accumulated lipid under stress conditions was cultivated for 12 h in darkness, and the effects of various conditions on lipid accumulation and biomass loss were analyzed. Under non-stress conditions, lipid contents dropped. Under certain stress conditions, conversely, the lipid contents were substantially improved so that net nightly endogenous lipid accumulation was observed. Under the optimal conditions (aeration mode with 0.10 vvm and 15% CO2, 5-10 mg L-1 of NO3 --N, 30-35 °C, approximate 2500 mg L-1 of biomass), the lipid content was doubled and increased lipid was approximately 180 mg L-1. Among stress conditions, N-deficiency had the most significant effect on endogenous lipid accumulation, and the optimum results were characterized under relatively low-N concentrations. Higher consistency between loss in carbohydrate and gain in lipid confirmed accumulated lipid endogenously conversed from carbohydrate. Based on the analyses of fatty acids profiles and prediction of kinematic viscosity, specific gravity, cloud point, cetane number and iodine value, it was confirmed that the quality of lipid obtained under optimal conditions complied with biodiesel quality standards. CONCLUSION: Via triggering endogenous lipid accumulation by stress conditions, even in darkness, SDEC-3M can synthesize enough lipid suitable for biodiesel feedstock. It implies that the lipid accumulation phase in two-phase strategy can be scheduled at night, and following biomass production stage in light, which should be a solution to improve the lipid yield and quality of large-scale outdoor photoautotrophic microalgae cultivation for biodiesel production.

[Moxibustion Plus Medication Can Relieve Refractory Nausea and Vomiting and Improve Quality of Life of Advanced Cancer Patients Undergoing Chemical Therapy].

OBJECTIVE: To explore the efficacy of moxibustion combined with medication in the treatment of refractory nausea and vomiting and quality of life (QOL) in advanced cancer patients. METHODS: A total of 266 advanced cancer patients with nausea and vomiting were randomly assigned to Metoclopramide group (M group, n＝70), Metoclopramide plus Haloperidol group (MH group, n＝65), moxibustion ＋ M group (n＝63), and moxibustion ＋ MH group (n＝68). Moxibustion was applied to bilateral Zusanli (ST 36), and Guanyuan (CV 4), Qihai (CV 6) for 20 min every time, twice a day for 2 weeks. The Rhodes' Index of nausea, Vomiting and Retching (INVR) was used for assessing the state of these symptoms in duration, frequency and severity (40 points), the 24-item Hamilton Depression Rating Scale (HAMD, 0－76 points) was employed to measure the patients' depression severity, and the Functional Assessment of Cancer Therapy-General (FACT-G, including physical, social/family, emotional, and functional dimensions, 27 items, 108 points) was adopted to measure the cancer patients' QOL. RESULTS: Following the treatment, the INVR and HAMD scores were significantly decreased in the M, MH, moxibusion＋M and moxibustion＋MH groups in comparison with their own pretreatment (P<0.05) and were significantly lower in the moxibustion＋MH group than in the M, MH and moxibustion＋M groups (P<0.05). The FACT-G scoring outcomes showed that the scores of physical well-being, emotional well-being, and total score of QOL were significantly higher in the MH, moxibustion＋M and moxibustion＋MH groups than in the M group, and were significantly higher in the moxibustion＋MH group than in the MH and moxibustion＋M groups (P<0.05). No significant differences were found between the MH and moxibustion＋M groups in the INVR and HAMD scores, and in the scores of physical well-being, emotional well-being and total score of QOL (P>0.05)．. CONCLUSION: Moxibustion plus Metoclopramide and Haloperidol can relieve refractory nausea and vomiting, and better depression and QOL in advanced cancer patients, being worthy of popularization in clinical practice.

Adjusting irradiance to enhance growth and lipid production of Chlorella vulgaris cultivated with monosodium glutamate wastewater.

Light is one of the most important factors affecting microalgae growth and biochemical composition. The influence of illumination on Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater (MSGW) was investigated. Six progressive illumination intensities (0, 30, 90, 150, 200 and 300µmol·m(-2)s(-1)), were used for C. vulgaris cultivation at 25°C. Under 150µmol·m(-2)s(-1), the corresponding specific light intensity of 750×10(-6)µmol·m(-2)s(-1) per cell, algae obtained the maximum biomass concentration (1.46g·L(-1)) on the 7th day, which was 3.5 times of that under 0µmol·m(-2)s(-1), and the greatest average specific growth rate (0.79 d(-1)) in the first 7days. The results showed the importance role of light in mixotrophic growth of C. vulgaris. High light intensities of 200 and 300µmol·m(-2)s(-1) would inhibit microalgae growth to a certain degree. The algal lipid content was the greatest (30.5%) at 150µmol·m(-2)s(-1) light intensity, which was 2.42 times as high as that cultured in dark. The protein content of C. vulgaris decreased at high light intensities of 200 and 300µmol·m(-2)s(-1). The effect of irradiance on carbohydrate content was inversely correlated with that on protein. The available light at an appropriate intensity, not higher than 200µmol·m(-2)s(-1), was feasible for economical cultivation of C. vulgaris in MSGW.

Effect of high-temperature stress on microalgae at the end of the logarithmic phase for the efficient production of lipid.

Efficient production of microalgae lipid is significant for the production of renewable biodiesel. In the present study, the high temperature of 40°C as stress environment was tested for stimulating lipid accumulation after the microalgae (Scenedesmus quadricauda) cells in suitable conditions grew to the end of the logarithmic phase. Different stress cultivation times of 1, 2, 3, 4, 5 and 6 days were studied. Interestingly, the lipid content and productivity reached 33.5% and 23.2 mg/L d after one day stress cultivation, showing substantial improvements of 39.6% and 33.3% compared with that in the untreated (day 0) microalgae cells, respectively. Longer stress time led to the decrease of biomass and lipid content compared with the untreated microalgae. However, a maximum protein content of 58.7% was obtained after six days. The stress cultivation at the end of the microalgae exponential phase for one day at a high temperature of 40°C could be a very useful industrial approach for efficiently promoting lipid content and biodiesel production.

The feasibility of using complex wastewater from a monosodium glutamate factory to cultivate Spirulina subsalsa and accumulate biochemical composition.

This paper is mainly observations on the growth and biomass accumulation of Spirulina subsalsa in modified Zarrouk medium supplemented with complex wastewater (CW, from a monosodium glutamate factory) in different concentrations. High ammonia in 75% and 100% CW inhibits algae growth, but maximum biomass production (2.86mgL(-1)) was obtained in 25% CW (concentration of CW in medium was 25%). Different CW concentration promoted biomass composition accumulation at different degrees, 41% of protein content in 25% CW and 18% of carbohydrate in 50% CW. In terms of economy, a concentration of 25% CW was suitable for protein production and 50% for lipid and carbohydrate production. These results suggested that CW is a feasible replacement in part for cultivation of S. subsalsa to economize input of water and nutrients.

Integrated campus sewage treatment and biomass production by Scenedesmus quadricauda SDEC-13.

The notion of wastewater treatment combined with biomass production is potential and prospective. Campus sewage was utilized twice in procession to cultivate the newly isolated microalgae Scenedesmus quadricauda SDEC-13. Nutrients was efficiently removed with the phosphorus and nitrogen removal efficiency nearly 100% and more than 70% respectively in twice use of campus sewage. Ammonium was consumed rapidly within five days in 1st use. There was no significant difference in the lipid and protein content but distinct difference in their respective productivity which is ascribed to the lower biomass productivity caused by limited nutrients in 2nd use. The diverse nutrient concentration in twice use of campus sewage and BG-11 had effects on the composition of fatty acids and amino acids. SDEC-13 performed better biodiesel quality compared with BG-11 medium and produced high quality protein when cultivated in campus sewage. Finally, the campus sewage after twice use reached the corresponding discharge standard.

The fate of Microcystis aeruginosa cells during the ferric chloride coagulation and flocs storage processes.

Microcystis blooms could cause severe problems for drinking water supplies with their associated microcystins (MCs). As the majority of MCs are retained inside the cells, the effective removal of the intact Microcystis cells to avoid the release of additional MCs plays an important role in drinking water treatment. This study evaluated the effect of ferric chloride (FeCl3) coagulation and the flocs storage process on the integrity of Microcystis aeruginosa cells and the intracellular MCs release (and possible degradation) in both processes. Multiple analysis techniques including scanning electron microscopy and chlorophyll fluorescence were used to assess the integrity of M. aeruginosa. In the coagulation process, the coagulant dosage and mechanical actions caused no cell damage, and all the cells remained intact. Furthermore, 100 mg/L FeCl3 was effective in removing the extracellular MCs. In the flocs storage process, a number of intracellular MCs were released into the supernatant, but the cells remained viable up to 10 d.

Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae.

Heterogeneous KOH/Al2O3 catalysts, synthesized by the wet impregnation method with different KOH loadings (20-40 wt%) and calcination temperatures from 400°C to 800°C, were used to produce biodiesel from Chlorella vulgaris biomass by in situ transesterification. The highest yield of biodiesel of 89.53±1.58% was achieved at calcination temperature of 700°C for 2 h and 35 wt% loading of KOH, and at the optimal reaction condition of 10 wt% of catalyst content, 8 mL/g of methanol to biomass ratio and at 60°C for 5 h. The characteristics of the catalysts were analysed by X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller.

Growth and lipid accumulation properties of microalgal Phaeodactylum tricornutum under different gas liquid ratios.

In this study, the effects of gas liquid ratio (GLR) on growth, lipid and fatty acid production of Phaeodactylum tricornutum were investigated. The positive linear relationships among specific growth rate, lipid content, fatty acid methyl ester content and GLR were built. GLR of 1.5vvm was considered as the optimum GLR for P. tricornutum growth and yielding oil, with highest biomass productivity (227.09mgL(-1)d(-1)), highest lipid productivity (48.48mgL(-1)d(-1)) and considerable amount fatty acids of saturated (50.16%) and monounsaturated (48.79%), which gave the finest compromise between oxidative stability and cold flow properties. pH variation was good controlled by the air bubbling velocity and algal photosynthesis. CO3(2-)/HCO3(-) ratio influenced the fatty acids synthesis, especially the component of C16:1. The average value of the most favorable composition C16:1 was 48.36%, which is comparable with other reports.

Identification and characterization of a freshwater microalga Scenedesmus SDEC-8 for nutrient removal and biodiesel production.

The selection of the right strains is of fundamental important to the success of the algae-based oil industry. From the six newly isolated microalgae strains tested for growth, fatty acid methyl ester (FAME) profiles and biodiesel properties, Scenedesmus SDEC-8, with favorable C16:0 fatty acids (73.43%), showed the best combined results. Then, morphological and molecular identification were examined. From the three wastewaters samples, Scenedesmus SDEC-8 showed good ability to yield oil and remove nutrients, which were comparable with other reports. In b artificial wastewater (TN 40 mg L(-1), TP 8 mg L(-1)), Scenedesmus SDEC-8 achieved the highest value of lipid productivity (53.84 mg L(-1) d(-1)), MUFA content (35.35%) and total FAME content (59.57±0.02 mg g(-1) DW), besides higher removal efficiencies of TN (99.18%) and TP (98.86%) helped effluent directly discharge and smaller dilution factor of N, P (3.3 and 9) which was good for lessening water utilization.

Mixotrophic growth and biochemical analysis of Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater.

Monosodium glutamate wastewater (MSGW) is a potential medium for microbial cultivation because of containing abundant organic nutrient. This paper seeks to evaluate the feasibility of growing Chlorella vulgaris with MSGW and assess the influence of MSGW concentration on the biomass productivity and biochemical compositions. The MSGW diluted in different concentrations was prepared for microalga cultivation. C. vulgaris growth was greatly promoted with MSGW compared with the inorganic BG11 medium. C. vulgaris obtained the maximum biomass concentration (1.02 g/L) and biomass productivity (61.47 mg/Ld) with 100-time diluted MSGW. The harvested biomass was rich in protein (36.01-50.64%) and low in lipid (13.47-25.4%) and carbohydrate (8.94-20.1%). The protein nutritional quality and unsaturated fatty acids content of algal increased significantly with diluted MSGW. These results indicated that the MSGW is a feasible alternative for mass cultivation of C. vulgaris.

Evaluation of the potential of 10 microalgal strains for biodiesel production.

In this study, the potential of 10 algae species for biodiesel production were evaluated by determining their fatty acid profiles, biodiesel properties besides growth rate, biomass concentration and lipid productivity. Among seven strains with high growth and lipid accumulation properties, excluding Kirchneriella lunaris and Lyngbya kuetzingii, five species Selenastrum capricornutum, Chlorella vulgaris, Scenedesmus obliqnus, Phaeodactylum tricornutum and Isochrysis sphacrica were finally selected for biodiesel production due to their possessing higher lipid productivity and favorable biodiesel properties. The best strain was P. tricornutum, with lipid content of 61.43 ± 0.95%, lipid productivity of 26.75 mgL(-1) d(-1), the favorable fatty acid profiles of C16-C18 (74.50%), C14:0 (11.68%) and C16:1 (22.34%) as well as suitable biodiesel properties of higher cetane number (55.10), lower iodine number (99.2 gI2/100g) and relatively low cloud point (4.47 °C).

Pseudomonas syringae pv. phaseolicola effector HopF1 inhibits pathogen-associated molecular pattern-triggered immunity in a RIN4-independent manner in common bean (Phaseolus vulgaris).

Plant pathogens usually promote pathogenesis by secreting effector proteins into host plant cells. One of the secreted effectors of Pseudomonas syringae pv. phaseolicola, the causative agent of halo-blight disease in common bean (Phaseolus vulgaris), HopF1, activates effector-triggered immunity (ETI) in a bean cultivar containing R1 resistance gene, but displays virulence function in a bean cultivar without the R1 gene. The virulence mechanism of the effector remained unknown, although it was identified more than a decade ago. Here we demonstrated that HopF1 can inhibit pathogen-associated molecular pattern-triggered immunity (PTI) in a susceptible bean cultivar Tendergreen. HopF1 directly interacted with two RPM1-interacting protein 4 (RIN4) orthologs of bean, PvRIN4a and PvRIN4b. Like RIN4 in Arabidopsis, both PvRIN4 orthologs negatively regulated the PTI responses in bean. However, the virulence function of HopF1 was enhanced in Tendergreen silencing PvRIN4. Furthermore, silencing PvRIN4a compromised the avrß1-induced hypersensitive response (HR), which previously was reported to be suppressed by HopF1. Together, these results demonstrated that PvRIN4 orthologs were not the virulence target of HopF1 for inhibiting PTI, but probably for interfering with ETI.

Human umbilical cord mesenchymal stem cells derived from Wharton's jelly differentiate into insulin-producing cells in vitro.

BACKGROUND: Islet transplantation is an effective way of reversing type I diabetes. However, islet transplantation is hampered by issues such as immune rejection and shortage of donor islets. Mesenchymal stem cells can differentiate into insulin-producing cells. However, the potential of human umbilical cord mesenchymal stem cells (huMSCs) to become insulin-producing cells remains undetermined. METHODS: We isolated and induced cultured huMSCs under islet cell culture conditions. The response of huMSCs were monitored under an inverted phase contrast microscope. Immunocytochemical and immunofluorescence staining methods were used to measure insulin and glucagon protein levels. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect gene expression of human insulin and PDX-1. Dithizone-staining was employed to determine the zinc contents in huMSCs. Insulin secretion was also evaluated through radioimmunoassay. RESULTS: HuMSCs induced by nicotinamide and ß-mercaptoethanol or by neurogenic differentiation 1 gene (NeuroD1) transfection gradually changed morphology from typically elongated fibroblast-shaped cells to round cells. They had a tendency to form clusters. Immunocytochemical studies showed positive expression of human insulin and glucagon in these cells in response to induction. RT-PCR experiments found that huMSCs expressed insulin and PDX-1 genes following induction and dithizone stained the cytoplasm of huMSCs a brownish red color after induction. Insulin secretion in induced huMSCs was significantly elevated compared with the control group (t = 6.183, P < 0.05). CONCLUSIONS: HuMSCs are able to differentiate into insulin-producing cells in vitro. The potential use of huMSCs in ß cell replacement therapy of diabetes needs to be studied further.