Core microbes identification and synthetic microbiota construction for the production of Xiaoqu light-aroma Baijiu.

Baijiu production has relied on natural inoculated Qu as a starter culture, causing the unstable microbiota of fermentation grains, which resulted in inconsistent product quality across batches. Therefore, revealing the core microbes and constructing a synthetic microbiota during the fermentation process was extremely important for stabilizing product quality. In this study, the succession of the microbial community was analyzed by high-throughput sequencing technology, and ten core microbes of Xiaoqu light-aroma Baijiu were obtained by mathematical statistics, including Acetobacter, Bacillus, Lactobacillus, Weissella, Pichia,Rhizopus, Wickerhamomyces, Issatchenkia, Saccharomyces, and Kazachstania. Model verification showed that the core microbiota significantly affected the composition of non-core microbiota (P < 0.01) and key flavor-producing enzymes (R > 0.8, P < 0.01), thus significantly affecting the flavor of base Baijiu. Simulated fermentation validated that the core microbiota can reproduce the fermentation process and quality of Xiaoqu light-aroma Baijiu. The succession of bacteria was mainly regulated by acidity and ethanol, while the fungi, especially non-Saccharomyces cerevisiae, were mainly regulated by the initial dominant bacteria (Acetobacter, Bacillus, and Weissella). This study will play an important role in the transformation of Xiaoqu light-aroma Baijiu fermentation from natural fermentation to controlled fermentation and the identification of core microbes in other fermented foods.

Exploring the impact of initial moisture content on microbial community and flavor generation in Xiaoqu baijiu fermentation.

Moisture is essential in microbiota succession and flavor formation during baijiu fermentation. However, it remains unknown how moisture content affects microbiota, metabolism, and their relationship. Here, we compared the difference in volatiles, microbiota characteristics, and potential functions with different initial moisture contents (50 %, 55 %, 60 %, 65 %, 70 %). Results showed that the ratio of ethyl acetate to ethyl lactate and total volatile compounds content increased as the moisture content was elevated from 50 % to 70 %. As increasing moisture content, fermentation system microbiota dominated by Lactobacillus was formed more rapidly. Lactobacillus, Dekkera, and Pediococcus were positively correlated with moisture, promoting the production of propanol, acetic acid, butyric acid, and 2-butanol. The complexity and stability of ecological networks enhanced as moisture content increased (R2 = 0.94, P = 0.004). Our study revealed that moisture-drive microbiota was a critical contributor to flavor formation, providing the theoretical basis for moisture control to regulate flavor compounds.

Revealing Potential Genes Affecting Flocculation and/or Viability of Saccharomyces pastorianus by Comparative Genomic Analysis.

Yeast flocculation and viability are critical factors in beer production. Adequate flocculation of yeast at the end of fermentation helps to reduce off-flavors and cell separation, while high viability is beneficial for yeast reuse. In this study, we used comparative genomics to analyze the genome information on Saccharomyces pastorianus W01, and its spontaneous mutant W02 with appropriate weakened flocculation ability (better off-flavor reduction performance) and unwanted decreased viability, to investigate the effect of different gene expressions on yeast flocculation or/and viability. Our results indicate that knockout of CNE1, CIN5, SIN3, HP-3, YPR170W-B, and SCEPF1_0274000100 and overexpression of CNE1 and ALD2 significantly decreased the flocculation ability of W01, while knockout of EPL1 increased the flocculation ability of W01. Meanwhile, knockout of CIN5, YPR170W-B, OST5, SFT1, SCEPF1_0274000100, and EPL1 and overexpression of SWC3, ALD2, and HP-2 decreased the viability of W01. CIN5, EPL1, SCEPF1_0274000100, ALD2, and YPR170W-B have all been shown to affect yeast flocculation ability and viability.

Oenological characteristics of two indigenous Starmerella bacillaris strains isolated from Chinese wine regions.

To broaden knowledge about the oenological characteristics of Starmerella bacillaris, the influence of two Chinese indigenous S. bacillaris strains on the conventional enological parameters and volatile compounds of Cabernet Sauvignon wines were investigated under different inoculation protocols (single inoculation and simultaneous/sequential inoculation with the commercial Saccharomyces cerevisiae EC1118). The results showed that the two S. bacillaris strains could complete alcohol fermentation alone under high sugar concentrations while increasing the content of glycerol and decreasing the content of acetic acid. Compared with wines fermented by EC1118 single inoculation, S. bacillaris single inoculation and S. bacillaris/EC1118 sequential inoculation increased the contents of isobutanol, ethyl isobutanoate, terpenes, and ketones and decreased the contents of isopentanol, phenylethyl alcohol, fatty acids, acetate esters, and total ethyl esters. Furthermore, for S. bacillaris/EC1118 simultaneous inoculation, the concentrations of ethyl esters were increased, contributing to a higher score of "floral" and "fruity" notes in agreement with sensory analysis. KEY POINTS: • S. bacillaris single and simultaneous/sequential inoculation. • Conventional enological parameters and volatile compounds were investigated. • S. bacillaris/EC1118 simultaneous fermentation increased ethyl esters.

Application Potential of Baijiu Non-Saccharomyces Yeast in Winemaking Through Sequential Fermentation With Saccharomyces cerevisiae.

To explore the potential application of non-Saccharomyces yeasts screened from Baijiu fermentation environment in winemaking, the effect of four Baijiu non-Saccharomyces yeasts (two Zygosaccharomyces bailii and two Pichia kudriavzevii) sequentially fermented with Saccharomyces cerevisiae on the physicochemical parameters and volatile compounds of wine was analyzed. The results indicated that there was no obvious antagonism between S. cerevisiae and Z. bailli or P. kudriavzevii in sequential fermentations, and all strains could be detected at the end of alcoholic fermentation. Compare with S. cerevisiae pure fermentation, Z. bailii/S. cerevisiae sequential fermentations significantly reduced higher alcohols, fatty acids, and ethyl esters and increased acetate esters; P. kudriavzevii/S. cerevisiae sequential fermentations reduced the contents of C6 alcohols, total higher alcohols, fatty acids, and ethyl esters and significantly increased the contents of acetate esters (especially ethyl acetate and 3-methylbutyl acetate). Sequential fermentation of Baijiu non-Saccharomyces yeast and S. cerevisiae improved the flavor and quality of wine due to the higher ester content and lower concentration of higher alcohols and fatty acids, non-Saccharomyces yeasts selected from Baijiu fermentation environment have potential applications in winemaking, which could provide a new strategy to improve wine flavor and quality.

Artificial nondirectional site-specific recombination systems.

Site-specific recombination systems (SRSs) are widely used in studies on synthetic biology and related disciplines. Nondirectional SRSs can randomly trigger excision, integration, reversal, and translocation, which are effective tools to achieve large-scale genome recombination. In this study, we designed 6 new nondirectional SRSs named Vika/voxsym1-4 and Dre/roxsym1-2. All 6 artificial nondirectional SRSs were able to generate random deletion and inversion in Saccharomyces cerevisiae. Moreover, all six SRSs were orthogonal to Cre/loxPsym. The pairwise orthogonal nondirected SRSs can simultaneously initiate large-scale and independent gene recombination in two different regions of the genome, which could not be accomplished using previous orthogonal systems. These SRSs were found to be robust while working in the cells at different growth stages, as well as in the different spatial structure of the chromosome. These artificial pairwise orthogonal nondirected SRSs offer newfound potential for site-specific recombination in synthetic biology.

The influence of dexmedetomidine on the emergence agitation of pediatric patients after the operations of sense organs under general anesthesia using sevoflurane.

BACKGROUND: We investigated the influence of dexmedetomidine on the emergence agitation of pediatric patients after ophthalmologic operation under general anesthesia using sevoflurane. METHODS: We selected 90 patients that were administered pediatric ophthalmologic operation for the study. The patients were randomly divided into 3 groups according to the administration way of drugs, i.e. the normal saline group (group S, N.=30), the midazolam group (group M, N.=30) and the dexmedetomidine group (group D, N.=30). For all patients, anesthesia induction was performed using sevoflurane before anesthesia, and the anesthesia was maintained in the operation with a combination of sevoflurane and remifentanil; laryngeal mask airway (LMA) was used for assisted ventilation. Ten minutes before the end of operation, 15 mL of 0.9% normal saline, 0.05 mg/kg of midazolam and 0.5 µg/kg of dexmedetomidine were administered to group S, group M and group D, respectively. After the operation, we observed the awakening time, time of the LMA removal as well as the recovery time in the Post Anesthesia Care Unit (PACU) of patients in all three groups. We evaluated the postoperative condition of sedation and agitation of the patients using Ramsay Sedation Scale, 5-point scale and Pediatric Anesthesia Emergence Deliriums Scale (PAED) and performed statistical analysis. RESULTS: In the comparisons of awakening time, time of the LMA removal as well as the recovery time, we found that group M was the longest sequentially followed by group D and group S with statistically significant differences (P<0.05). While the comparison of the scores of Ramsay Sedation Scale revealed that group D scored highest followed by group M and group S with statistically significant differences (P<0.05), both of the comparisons of the scores of 5-point scale and PAED Scale showed that group D scored the lowest, followed by group M and group S in sequence with statistically significant differences (P<0.05). CONCLUSIONS: Dexmedetomidine can significantly lower the incidence of emergence agitation of pediatric patients after the ophthalmologic operation under sevoflurane anesthesia.

Investigation of the role of miR-221 in diabetic peripheral neuropathy and related molecular mechanisms.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes, but the molecular mechanisms of DPN are still unclear. OBJECTIVES: To investigate the role of miR-221 in DPN and the related molecular mechanisms. MATERIAL AND METHODS: Streptozotocin (STZ) was used to establish an in vivo DPN model. An in vitro DPN model was established using high glucose-induced SH-SY5Y cells. The pain condition of rats was measured by evaluating the 50% paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). Serum exosomes were extracted and identified. Expression of miR-221 in serum exosomes and serum SOCS3 expression were determined using reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Western blotting was used to measure the protein levels of SOCS3, bradykinin (BK) and prostaglandin E2 (PEG2). The dual luciferase reporter assay was performed to confirm SOCS3 3'-UTR as a target of miR-221. The serum or cell supernatant levels of PEG2, BK, interleukin (IL)-6, IL-1ß, and tumor necrosis factor alpha (TNF-α) were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: Induction of the lenti-miR-221 inhibitor significantly decreased the expression of miR-221 in DPN rats. Both 50% PWT and PWL values were markedly decreased in DPN rats. When miR-221 was inhibited, the 50% PWT and PWL values were both significantly increased. Knockdown of miR-221 significantly increased the expression of SOCS3 and decreased the expression of NF-κB. Furthermore, knockdown of miR-221 remarkably decreased the expression of PEG2, BK, IL-6, IL-1ß, and TNF-α in both STZ-treated DPN rats and high glucose-induced SH-SY5Y cells, which was reversed by inhibition of SOCS3. The dual luciferase reporter assay showed that miR-221 directly targeted and negatively regulated SOCS3. CONCLUSIONS: Inhibition of miR-221 can reduce pain and decrease expression of inflammatory factors through targeting SOCS3 in DPN.

Expressions of Fib, IL-12 in Serum of Neonatal Necrotizing Enterocolitis and Their Correlation with Clinicopathological Features.

BACKGROUND: To investigate the expressions of fibrinogen (Fib) and Interleukin-12 (IL-12) in serum of neonatal necrotizing enterocolitis (NEC), and to analyze the correlation between the two and their relationship with clinicopathological features. METHODS: Forty two children with NEC treated in Xuzhou Children's Hospital, Xuzhou Medical University Xuzhou, China from 2016-2019 were selected as an observation group and 40 children who underwent physical examination at the same period as a control group. The expression levels of Fib and IL-12 in the serum of two groups were detected by ELISA. The correlation between Fib and IL-12 in the observation group and the correlation among the expressions of Fib, IL-12, the clinicopathological features and common examination indexes of the children with NEC were investigated by Pearson correlation analysis. RESULTS: The levels of Fib and IL-12 in the serum of the children in observation group were significantly higher than those in the control group were (P<0.05). There was a significant positive correlation between the levels of Fib and IL-12 in the serum of the children in observation group (P<0.05). The expression levels of Fib, IL-12 were not significantly correlated with sex and age of NEC children, but correlated with vomiting, diarrhea, bloody stool and bradycardia in NEC children (P<0.05). Fib and IL-12 were positively correlated with erythrocyte level (P<0.05) and negatively correlated with platelet level. CONCLUSION: The expressions of Fib and IL-12 in the serum of NEC children can objectively predict the severity of NEC.

Curcumin improves necrotising microscopic colitis and cell pyroptosis by activating SIRT1/NRF2 and inhibiting the TLR4 signalling pathway in newborn rats.

This study aimed to explore comprehensively the biological function of curcumin, and its underlying mechanism, in protecting from necrotising microscopic colitis in newborn rats. A total of 20 normal healthy rats were selected, and a necrotising enterocolitis (NEC) model was established. After hypoxia and hypothermia stimulation, these rats were treated with different doses of curcumin (control group, NEC model group, NEC+20 mg/kg curcumin and NEC+50 mg/kg curcumin). Inflammation was identified using hematoxylin and eosin staining, and inflammatory factors were detected via ELISA. The mRNA and protein levels of SIRT1, NRF2, TLR4, NLRP3 and caspase-1 were determined by quantitative RT-PCR and Western blotting, respectively. Curcumin improved the inflammatory condition of NEC and inhibited the expression of inflammatory factors in NEC newborn rat intestinal tissue. Furthermore, the SIRT1/NRF2 pathway was inhibited in the intestinal tissue of NEC newborn rats, whereas curcumin treatment induced the activation of the SIRT1/NRF2 pathway and inhibited TLR4 expression in these animals. In addition, curcumin could also inhibit the expression of inflammatory factors and alleviate the LPS/ATP-induced focal death pathway in intestinal epithelial cells through the SIRT1 pathway. Curcumin can improve necrotising microscopic colitis and cell pyroptosis by attenuating NEC-induced inhibition of SIRT1/NRF2 and inhibiting the TLR4 signalling pathway in newborn rats.

Aquaporin­4 deletion ameliorates enterovirus 71 infection in mice.

Aquaporin-4 (AQP4) is a major water channel of the central nervous system. The present study was designed to determine whether AQP4 deletion could ameliorate enterovirus (EV) 71 infection­induced hand, foot and mouth disease (HFMD) by inhibiting inflammation and apoptosis in mice. EV 71 strains were injected into neonatal BALB/c mice to induce HFMD. Western blotting and ELISA were used to measure the protein expression and cytokine levels. The levels of AQP4 mRNA and protein in the brain were increased in EV 71­infected mice, while the survival rate and health score were improved in AQP4­knockout (KO) mice with EV 71 infection. The EV 71 infection­induced increases of tumor necrosis factor­α, interleukin (IL)­1ß, IL­6, monocyte chemotactic protein­1, interferon (IFN)­α and IFN­Î³ in plasma and brain were inhibited in AQP4­KO mice. AQP4 deletion reversed the decreased levels of Bcl2 and Bcl2/Bax, and the increased levels of Bax induced by EV 71 infection in the brain. These results demonstrated that AQP4 deletion ameliorated EV 71 induced­HFMD via inhibiting inflammation and apoptosis in mice.

Engineering Pichia pastoris to improve S-adenosyl- l-methionine production using systems metabolic strategies.

S-adenosyl-l-methionine (SAM) is a highly valued chemical that can be used as a dietary supplement and has been used to treat depression, osteoarthritis, and liver problems as well. We adopted systems metabolic engineering strategies to improve SAM production in a high-producing strain (GS115/DS56). First, the cystathionine ß-synthase gene CYS4 was downregulated using a weak promoter PG12 to reduce the removal of homocysteine from SAM cycle, thus leading to a 48.8% increase in the SAM titer (1.68 g/L) from the strain G12-CBS, while preventing cysteine auxotrophy induced by deletion of this essential gene. Subsequently, the SAM titer of G12-CBS was improved to 13.01 g/L in 15-L fed-batch fermentation using the optimal l-methionine feeding strategy. Finally, based on comparative transcriptomics, five genes were chosen and overexpressed for further enhancement of SAM production. Among them, GDH2 and ACS2 exhibited positive effects, and the additional overexpression of GDH2 led to a 52.3% increase of titer (2.71 g/L) in shake flask culture. Therefore, the engineered Pichia pastoris strains can be utilized in industrial production of SAM using a simple and cost-effective process, and these approaches could be employed for improving the production of other chemicals by P. pastoris.

Overexpressed FOXO3 improves inflammatory status in mice by affecting NLRP3-mediated cell coronation in necrotizing colitis mice.

OBJECTIVE: To investigate the relationship between FOXO3 overexpression and NLRP3 and explore the effect of FOXO3 on necrotizing colitis. METHODS: 100 clean grade newborn SD (Sprague Dawley) rats were randomly divided into 4 groups: NEC group, NEC + FOXO3a group, NEC + NC group and control group. NEC rat model was established by hypoxia + hypothermia stimulation; HE staining was used for detection of the inflammation of intestinal tissue. The histological scores of intestinal tissues were histologically scored, generally, there were three types of inflammatory scoring systems including anatomically based systems, severity-based systems and quality of life systems (Lim et al., 2015) and in this study we utilized severity-based systems by HE staining. Human intestinal epithelial cell line was transfected with recombinant plasmid overexpressing FOXO3a and recombinant plasmid overexpressing NLRP3, and divided into control group, LPS group, LPS + NC group, LPS + FOXO3a group and LPS + FOXO3a + NLRP3 group; Caspase-1 was used for the detection of pyroptosis. The expressions of FOXO3a, NLRP3, cleaved Caspase-1 and the expression of TLR4 in TLR4 signaling pathway were detected by RT-qPCR and WB. IL-1ß, IL-6, IL-18 and TNF-α were detected by ELISA. RESULTS: (1) FOXO3a is under-expressed and NLRP3 is highly expressed in NEC neonatal rat intestinal tissue. (2) The inflammatory condition of intestinal tissue in NEC + FOXO3a group was improved compared with NEC group (P < 0.05). (3) FOXO3a was highly expressed in NEC + FOXO3a group. The expression of IL-1ß, IL-6, IL-18, SOD and MDA in NEC + FOXO3a group was lower than that in NEC group. (4) The expression of IL-1ß, IL-6, IL-18, SOD and MDA in intestinal epithelial cells of LPS + FOXO3a group was lower than other groups. (5) Overexpression of FOXO3a inhibits LPS-induced pyroptotic cell death in intestinal epithelial cells by inhibiting NLRP3. CONCLUSION: Overexpression of FOXO3 in mice with necrotizing colitis can improve inflammatory conditions in mice by affecting NLRP3-mediated cell caking.

Comparison of desflurane and sevoflurane on postoperative recovery quality after tonsillectomy and adenoidectomy in children.

Comparison of desflurane and sevoflurane on the postoperative recovery quality after tonsillectomy and adenoidectomy in children was carried out. A retrospective analysis was performed on the medical records of 165 children who underwent tonsil and adenoid radiofrequency ablation under low-temperature plasma and were admitted to the Xuzhou Children's Hospital, Xuzhou Medical University from February 2014 to May 2017. In total, 79 children with sevoflurane anesthesia were in the sevoflurane group, and 86 children with desflurane anesthesia in the desflurane group. The non-invasive blood pressure (NIBP), heart rate (HR) and oxygen saturation (SpO2) level, the postoperative sedation (Ramsay) scores, the modified objective pain score (MOPS) of children were recorded. The pediatric anesthesia emergence delirium (PAED) scores of children were recorded. Children in the sevoflurane group had longer operation time, anesthesia time, extubation time and coincidence time than those in the desflurane group (P<0.05). At the beginning of operation (t1), 10 min after operation (t2), at the time of entering anesthesia recovery room (t3), at the time of tracheal catheter extubated (t4), 10 min after extubation (t5), and at the time of leaving the anesthesia recovery room (t6), children in the sevoflurane had higher NISBP and NIDBP, lower HR than those in the desflurane group (P<0.05). At the time of the tracheal catheter extubation (c2), 10 min after extubation (c3), 30 min after extubation (c4), children in the sevoflurane group had lower Ramsay scores and higher PAED scores than those in the desflurane group (P<0.05). More suitable as an anesthetic maintenance drug for tonsillectomy and adenoidectomy in children, desflurane has a better anesthetic effect and is safer. In addition, children with desflurane anesthesia have high postoperative recovery quality and quick recovery in the short term, with better sedative and analgesic effects. Therefore, it is worthy of promotion in clinic practice.

Efficacy and safety of propofol in preventing emergence agitation after sevoflurane anesthesia for children.

Application of propofol in preventing emergence agitation after sevoflurane anesthesia in children was evaluated. Clinical data of 200 children who received sevoflurane anesthesia in Children's Hospital of Xuzhou Medical University were retrospectively analyzed. Among them, 120 patients who received inhaled sevoflurane for pediatric anesthesia and intravenous infusion of propofol (2 mg/kg) were included in observation group. The remaining 80 cases who were directly anesthetized by sevoflurane alone were the control group. T PAED scores, modified Aldrete scores, extubation time, PACU time and adverse reactions (gastrointestinal tract and respiratory response) were analyzed and compared between the control and observation group. PAED scores, extubation time, PACU time and incidence of adverse reactions were significantly lower in observation than in control group, and the modified Aldrete scores were higher in observation than in control group (P<0.05). Spearman's correlation analysis showed that the PAED scores were negatively correlated with modified Aldrete scores and positively correlated with extubation time. There was positive correlation between the PACU time and incidence of adverse reactions and between the PAED scores and extubation time. There was negative correlation between PACU time and incidence of adverse reactions and between Aldrete scores and extubation time (P<0.05). Therefore, we conclude that propofol can be used to prevent agitation after sevoflurane anesthesia in children.

Inhibition of miR-124 improves neonatal necrotizing enterocolitis via an MYPT1 and TLR9 signal regulation mechanism.

BACKGROUNDS: Necrotizing enterocolitis (NEC) was one of the main causes of morbidity and mortality in neonates. Our objective was to detect the mechanism of miR-124 in small bowel tissues of NEC. METHODS: Hematoxylin and eosin (H&E) staining was used to detect the repair of the damaged tissues in rat NEC model. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to evaluate the cell apoptosis level in intestinal tissue. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the messenger RNA (mRNA) expression level of miR-124, Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), myosin phosphatase target subunit 1 (MYPT1), and Toll-like receptor 9 (TLR9) in NEC tissues and IEC-6 cells. Luciferase reporter assay was used to verify whether ROCK1 is a direct target of miR-124. RESULTS: miR-124 was overexpressed in the NEC tissues, while ROCK1 and MYPT1 was downregulated in the NEC tissues. Inhibition of miR-124, suppressed the intestinal cell apoptosis and promoted the expression of ROCK1 and MYPT1. What is more, overexpression of miR-124 could inhibit the expression of ROCK1, TLR9, and MYPT1. Luciferase assay confirmed that miR-124 can regulate the transcriptional activity of ROCK1 through binding its 3'-UTR region. CONCLUSION: miR-124 was a promoter of NEC, which promotes the intestine cell apoptosis and inflammatory cell infiltration through the inhibition of TLR9 expression by targeting ROCK1.

Ethylenediamine pretreatment of corn stover facilitates high gravity fermentation with low enzyme loading.

This work investigated the effect of ethylenediamine pretreatment on reducing enzyme loading in high gravity fermentation. At optimal conditions of ethylenediamine pretreatment, 85.5% lignin was removed. Enzyme adsorption analysis using a fluorescent cellulose-binding protein showed 35.2% increase of productive adsorption of enzymes to ethylenediamine pretreated biomass, which was caused by high delignification and dramatically increased surface roughness and porosity. In SScF at 15% glucan loading, up to 82.2 g/L ethanol was achieved with a relatively low enzyme loading of 3.6 FPU/g dry matter. It suggested that the remarkably high digestibility of EDA pretreated corn stover could effectively reduce the enzyme loading in the high gravity fermentation of cellulosic ethanol.

Genome-wide landscape of position effects on heterogeneous gene expression in Saccharomyces cerevisiae.

BACKGROUND: Integration of heterogeneous genes is widely applied in synthetic biology and metabolic engineering. However, knowledge about the effect of integrative position on gene expression remains limited. RESULTS: We established a genome-wide landscape of position effect on gene expression in Saccharomyces cerevisiae. The expression cassette of red fluorescence protein (RFP) gene was constructed and inserted at 1044 loci, which were scattered uniformly in the yeast genome. Due to the different integrative loci on the genome, the maximum relative intensity of RFP is more than 13-fold over the minimum. Plots of the number of strains to RFP relative intensity showed normal distribution, indicating significant position effect on gene expression in yeast. Furthermore, changing the promoters or reporter genes, as well as carbon sources, revealed little consequences on reporter gene expression, indicating chromosomal location is the major determinant of reporter gene expression. CONCLUSIONS: We have examined the position effects to integration genes expression in large number loci around whole genome in S. cerevisiae. The results could guide the design of integration loci for exogenous genes and pathways to maximize their expression in metabolic engineering.