Multi-omics association study of hexadecane degradation in haloarchaeal strain Halogranum rubrum RO2-11.

Haloarchaea with the capacity to degrade alkanes is promising to deal with petroleum pollution in hypersaline environments. However, only a limited number of haloarchaeal species are investigated, and their pathway and mechanism for alkane degradation remain unclear. In this study, Halogranum rubrum RO2-11, a haloarchaeal strain, verified the ability to degrade kerosene and hexadecane in 184 g/L NaCl, with 53% and 52% degradation rates after 9 and 4 days, respectively. Genome sequencing and gene annotation indicated that strain RO2-11 possesses a complete potential alkane-degrading pathway, of which alkane hydroxylases may include CYP450, AlmA, and LadA. Transcriptome and metabolome analyses revealed that the upregulation of related genes in TCA cycle, lysine biosynthesis, and acetylation may help improve hexadecane degradation. Additionally, an alternative degrading pathway of hexadecane based on dual-terminal ß-oxidation may occur in strain RO2-11. It is likely to be the first report of alkane degradation by the genus Halogranum, which may be helpful for applications of oil-pollution bioremediation under high-salt conditions.

Engineered probiotic E.coli Nissle 1917 for release PTEN to improve the tumor microenvironment and suppress tumor growth.

The cancer is one of the diseases of serious threat to people's health and life nowadays. But heterogeneity, drug resistance and treatment side effects of cancer, traditional treatments still have limitations. Tumor-targeting probiotics with a well-established Biosafety and efficient targeting as a delivery vectors to deliver anticancer genes or antitumor drugs to tumor microenvironment has attracted much attention in cancer therapies. In this study, E.coil Nissle 1917 (EcN) was utilized to deliver eukaryotic anti-tumor protein PTEN to tumor microenvironment and suppress tumor growth. Therefore, the EcN (PTEN) was developed. Our results demonstrated that EcN (PTEN) could colonize the tumor site accurately and inhibit the growth of colorectal cancer cells in tumor-bearing mice. It is worth noting that the tumor microenvironment of the treated mice showed significant recruitment of and M1 macrophages, neutrophils and T lymphocytes. No toxicity was observed in the normal tissues during the experiments. This research show the probiotic EcN(PTEN) holds the promise of becoming a powerful weapon against cancer and expected to provide more effective treatments for cancer patients.

Enrichment of microbial consortia for MEOR in crude oil phase of reservoir-produced liquid and their response to environmental disturbance.

Developing microbial consortiums is necessary for microbial enhanced oil recovery (MEOR) in heavy crude oil production. The aqueous phase of produced fluid has long been considered an ideal source of microorganisms for MEOR. However, it is recently found that rich microorganisms (including hydrocarbon-degrading bacteria) are present in the crude oil phase, which is completely different from the aqueous phase of produced fluid. So, in this study, the microbial consortia from the crude oil phase of produced fluids derived from four wells were enriched, respectively. The microbial community structure during passage was dynamically tracked, and the response of enriched consortia to successive disturbance of environmental factors was investigated. The results showed the crude oil phase had high microbial diversity, and the original microbial community structure from four wells was significantly different. After ten generations of consecutive enrichment, different genera were observed in the four enriched microbial consortia, namely, Geobacillus, Bacillus, Brevibacillus, Chelativorans, Ureibacillus, and Ornithinicoccus. In addition, two enriched consortia (eG1614 and eP30) exhibited robustness to temperature and oxygen perturbations. These results further suggested that the crude oil phase of produced fluids can serve as a potential microbial source for MEOR.

The responses of mesophilic and thermophilic anaerobic digestion of municipal sludge to periodic fluctuation disturbance of organic loading rate.

Fluctuation disturbance of organic loading rate (OLR) is common in actual anaerobic digestion (AD), but its effects on AD of municipal sludge gets little attention. This study investigated the responses of reactor performance and active microbial community in mesophilic and thermophilic AD of municipal sludge before, during and after OLR periodic fluctuation disturbance. The performance of both reactors were similar before and after disturbance although some parameter values changed during the disturbance, which indicated their enough buffer capacity to OLR periodic fluctuation. Different microbial community at RNA level was observed in the two reactors. When the OLR disturbance commenced, the microbial community changed greatly in thermophilic AD. Error and attack tolerance of the microbial network was analyzed in order to learn the response mechanisms to OLR disturbance. The results assisted that the thermophilic microbial community was more vulnerable, but the reactor performance of which could be maintained using the functional redundancy strategy under OLR fluctuation disturbance.

Effects of a Pirin-like protein on strain growth and spinosad biosynthesis in Saccharopolyspora spinosa.

Pirin family proteins perform a variety of biological functions and widely exist in all living organisms. A few studies have shown that Pirin family proteins may be involved in the biosynthesis of antibiotics in actinomycetes. However, the function of Pirin-like proteins in S. spinosa is still unclear. In this study, the inactivation of the sspirin gene led to serious growth defects and the accumulation of H2O2. Surprisingly, the overexpression and knockout of sspirin slightly accelerated the consumption and utilization of glucose, weakened the TCA cycle, delayed sporulation, and enhanced sporulation in the later stage. In addition, the overexpression of sspirin can enhance the ß-oxidation pathway and increase the yield of spinosad by 0.88 times, while the inactivation of sspirin hardly produced spinosad. After adding MnCl2, the spinosad yield of the sspirin overexpression strain was further increased to 2.5 times that of the wild-type strain. This study preliminarily revealed the effects of Pirin-like proteins on the growth development and metabolism of S. spinosa and further expanded knowledge of Pirin-like proteins in actinomycetes. KEY POINTS: • Overexpression of the sspirin gene possibly triggers carbon catabolite repression (CCR) • Overexpression of the sspirin gene can promote the synthesis of spinosad • Knockout of the sspirin gene leads to serious growth and spinosad production defects.

Regulatory mechanism of Haa1p and Tye7p in Saccharomyces cerevisiae when fermenting mixed glucose and xylose with or without inhibitors.

BACKGROUND: Various inhibitors coexist in the hydrolysate derived from lignocellulosic biomass. They inhibit the performance of Saccharomyces cerevisiae and further restrict the development of industrial bioethanol production. Transcription factors are regarded as targets for constructing robust S. cerevisiae by genetic engineering. The tolerance-related transcription factors have been successively reported, while their regulatory mechanisms are not clear. In this study, we revealed the regulation mechanisms of Haa1p and Tye7p that had outstanding contributions to the improvement of the fermentation performance and multiple inhibitor tolerance of S. cerevisiae. RESULTS: Comparative transcriptomic analyses were applied to reveal the regulatory mechanisms of Haa1p and Tye7p under mixed sugar fermentation conditions with mixed inhibitors [acetic acid and furfural (AFur)] or without inhibitor (C) using the original strain s6 (S), the HAA1-overexpressing strain s6H3 (H), and the TYE7-overexpressing strain s6T3 (T). The expression of the pathways related to carbohydrate, amino acid, transcription, translation, cofactors, and vitamins metabolism was enhanced in the strains s6H3 and s6T3. Compared to C_H vs. C_S group, the unique DEGs in AFur_H vs. AFur_S group were further involved in oxidative phosphorylation, purine metabolism, vitamin B6 metabolism, and spliceosome under the regulation of Haa1p. A similar pattern appeared under the regulation of Tye7p, and the unique DEGs in AFur_T vs. AFur_S group were also involved in riboflavin metabolism and spliceosome. The most significant difference between the regulations of Haa1p and Tye7p was the intracellular energy supply. Haa1p preferred to enhance oxidative phosphorylation, while Tye7p tended to upregulate glycolysis/gluconeogenesis. CONCLUSIONS: Global gene expressions could be rewired with the overexpression of HAA1 or TYE7. The positive perturbations of energy and amino acid metabolism were beneficial to the improvement of the fermentation performance of the strain. Furthermore, strengthening of key cofactor metabolism, and transcriptional and translational regulation were helpful in improving the strain tolerance. This work provides a novel and comprehensive understanding of the regulation mechanisms of Haa1p and Tye7p in S. cerevisiae.

A TetR family transcriptional regulator, SP_2854 can affect the butenyl-spinosyn biosynthesis by regulating glucose metabolism in Saccharopolyspora pogona.

BACKGROUND: Butenyl-spinosyn produced by Saccharopolyspora pogona exhibits strong insecticidal activity and a broad pesticidal spectrum. Currently, important functional genes involve in butenyl-spinosyn biosynthesis remain unknown, which leads to difficulty in efficiently understanding its regulatory mechanism, and improving its production by metabolic engineering. RESULTS: Here, we identified a TetR family transcriptional regulator, SP_2854, that can positively regulate butenyl-spinosyn biosynthesis and affect strain growth, glucose consumption, and mycelial morphology in S. pogona. Using targeted metabolomic analyses, we found that SP_2854 overexpression enhanced glucose metabolism, while SP_2854 deletion had the opposite effect. To decipher the overproduction mechanism in detail, comparative proteomic analysis was carried out in the SP-2854 overexpressing mutant and the original strain, and we found that SP_2854 overexpression promoted the expression of proteins involved in glucose metabolism. CONCLUSION: Our findings suggest that SP_2854 can affect strain growth and development and butenyl-spinosyn biosynthesis in S. pogona by controlling glucose metabolism. The strategy reported here will be valuable in paving the way for genetic engineering of regulatory elements in actinomycetes to improve important natural products production.

Microbial communities in crude oil phase and filter-graded aqueous phase from a Daqing oilfield after polymer flooding.

AIMS: The aim was to characterize indigenous micro-organisms in oil reservoirs after polymer flooding (RAPF). METHODS: The microbial communities in the crude oil phase (Oil) and in the filter-graded aqueous phases Aqu0.22 (>0.22 µm) and Aqu0.1 (0.1-0.22 µm) were investigated by 16S rRNA gene high-throughput sequencing. RESULTS: Indigenous micro-organisms related to hydrocarbon degradation prevailed in the three phases of each well. However, obvious differences in bacterial compositions were observed amongst the three phases of the same well and amongst the same phase of different wells. The crude oil and Aqu0.22 shared many dominant bacteria. Aqu0.1 contained a unique bacterial community in each well. Most bacteria in Aqu0.1 were affiliated to culturable genera, suggesting that they may adapt to the oil reservoir environment by reduction of cell size. Contrary to the bacterial genera, archaeal genera were similar in the three phases but varied in relative abundances. The observed microbial differences may be driven by specific environmental factors in each oil well. CONCLUSIONS: The results suggest an application potential of microbial enhanced oil recovery (MEOR) technology in RAPF. The crude oil and Aqu0.1 contain many different functional micro-organisms related to hydrocarbon degradation. Both should not be overlooked when investing and exploring the indigenous micro-organisms for MEOR. SIGNIFICANCE AND IMPACT OF THE STUDY: This work facilitates the understanding of microbial community structures in RAPF and provides information for microbial control in oil fields.

Effect of pII key nitrogen regulatory gene on strain growth and butenyl-spinosyn biosynthesis in Saccharopolyspora pogona.

PII signal transduction proteins are widely found in bacteria and plant chloroplast, and play a central role in nitrogen metabolism regulation, which interact with many key proteins in metabolic pathways to regulate carbon/nitrogen balance by sensing changes in concentrations of cell-mediated indicators such as α-ketoglutarate. In this study, the knockout strain Saccharopolyspora pogona-ΔpII and overexpression strain S. pogona-pII were constructed using CRISPR/Cas9 technology and the shuttle vector POJ260, respectively, to investigate the effects on the growth and secondary metabolite biosynthesis of S. pogona. Growth curve, electron microscopy, and spore germination experiments were performed, and it was found that the deletion of the pII gene inhibited the growth to a certain extent in the mutant. HPLC analysis showed that the yield of butenyl-spinosyn in the S. pogona-pII strain increased to 245% than that in the wild-type strain while that in S. pogona-ΔpII decreased by approximately 51%. This result showed that the pII gene can promote the growth and butenyl-spinosyn biosynthesis of S. pogona. This research first investigated PII nitrogen metabolism regulators in S. pogona, providing significant scientific evidence and a research basis for elucidating the mechanism by which these factors regulate the growth of S. pogona, optimizing the synthesis network of butenyl-spinosyn and constructing a strain with a high butenyl-spinosyn yield. KEY POINTS: • pII key nitrogen regulatory gene deletion can inhibit the growth and development of S. pogona. • Overexpressed pII gene can significantly promote the butenyl-spinosyn biosynthesis. • pII gene can affect the amino acid circulation and the accumulation of butenyl-spinosyn precursors in S. pogona.

Improving Acetic Acid and Furfural Resistance of Xylose-Fermenting Saccharomyces cerevisiae Strains by Regulating Novel Transcription Factors Revealed via Comparative Transcriptomic Analysis.

Acetic acid and furfural are the two prevalent inhibitors coexisting with glucose and xylose in lignocellulosic hydrolysate. The transcriptional regulations of Saccharomyces cerevisiae in response to acetic acid (Aa), furfural (Fur), and the mixture of acetic acid and furfural (Aa_Fur) were revealed during mixed glucose and xylose fermentation. Carbohydrate metabolism pathways were significantly enriched in response to Aa, while pathways of xenobiotic biodegradation and metabolism were significantly enriched in response to Fur. In addition to these pathways, other pathways were activated in response to Aa_Fur, i.e., cofactor and vitamin metabolism and lipid metabolism. Overexpression of Haa1p or Tye7p improved xylose consumption rates by nearly 50%, while the ethanol yield was enhanced by nearly 8% under acetic acid and furfural stress conditions. Co-overexpression of Haa1p and Tye7p resulted in a 59% increase in xylose consumption rate and a 12% increase in ethanol yield, revealing the beneficial effects of Haa1p and Tye7p on improving the tolerance of yeast to mixed acetic acid and furfural.IMPORTANCE Inhibitor tolerance is essential for S. cerevisiae when fermenting lignocellulosic hydrolysate with various inhibitors, including weak acids, furans, and phenols. The details regarding how xylose-fermenting S. cerevisiae strains respond to multiple inhibitors during fermenting mixed glucose and xylose are still unknown. This study revealed the transcriptional regulation mechanism of an industrial xylose-fermenting S. cerevisiae strain in response to acetic acid and furfural. The transcription factor Haa1p was found to be involved in both acetic acid and furfural tolerance. In addition to Haa1p, four other transcription factors, Hap4p, Yox1p, Tye7p, and Mga1p, were identified as able to improve the resistance of yeast to these two inhibitors. This study underscores the feasibility of uncovering effective transcription factors for constructing robust strains for lignocellulosic bioethanol production.

Effects of acuC on the growth development and spinosad biosynthesis of Saccharopolyspora spinosa.

BACKGROUND: Acetoin utilization protein (acuC) is a type I histone deacetylase which is highly conserved in bacteria. The acuC gene is related to the acetylation/deacetylation posttranslational modification (PTM) system in S. spinosa. Spinosyns, the secondary metabolites produced by Saccharopolyspora spinosa, are the active ingredients in a family of insect control agents. However, the specific functions and influences of acuC protein in S. spinosa are yet to be characterized. RESULTS: The knockout strain and overexpression strain were constructed separately with the shuttle vector pOJ260. The production of spinosyns A and D from S. spinosa-acuC were 105.02 mg/L and 20.63 mg/L, which were 1.82-fold and 1.63-fold higher than those of the wild-type strain (57.76 mg/L and 12.64 mg/L), respectively. The production of spinosyns A and D from S. spinosa-ΔacuC were 32.78 mg/L and 10.89 mg/L, respectively. The qRT-PCR results of three selected genes (bldD, ssgA and whiA) confirmed that the overexpression of acuC affected the capacities of mycelial differentiation and sporulation. Comparative proteomics analysis was performed on these strains to investigate the underlying mechanism leading to the enhancement of spinosad yield. CONCLUSIONS: This study first systematically analysed the effects of overexpression acuC on the growth of S. spinosa and the production of spinosad. The results identify the differentially expressed proteins and provide evidences to understand the acetylation metabolic mechanisms which can lead to the increase of secondary metabolites.

Bacterioferritin: a key iron storage modulator that affects strain growth and butenyl-spinosyn biosynthesis in Saccharopolyspora pogona.

BACKGROUND: Butenyl-spinosyn, produced by Saccharopolyspora pogona, is a promising biopesticide due to excellent insecticidal activity and broad pesticidal spectrum. Bacterioferritin (Bfr, encoded by bfr) regulates the storage and utilization of iron, which is essential for the growth and metabolism of microorganisms. However, the effect of Bfr on the growth and butenyl-spinosyn biosynthesis in S. pogona has not been explored. RESULTS: Here, we found that the storage of intracellular iron influenced butenyl-spinosyn biosynthesis and the stress resistance of S. pogona, which was regulated by Bfr. The overexpression of bfr increased the production of butenyl-spinosyn by 3.14-fold and enhanced the tolerance of S. pogona to iron toxicity and oxidative damage, while the knockout of bfr had the opposite effects. Based on the quantitative proteomics analysis and experimental verification, the inner mechanism of these phenomena was explored. Overexpression of bfr enhanced the iron storage capacity of the strain, which activated polyketide synthase genes and enhanced the supply of acyl-CoA precursors to improve butenyl-spinosyn biosynthesis. In addition, it induced the oxidative stress response to improve the stress resistance of S. pogona. CONCLUSION: Our work reveals the role of Bfr in increasing the yield of butenyl-spinosyn and enhancing the stress resistance of S. pogona, and provides insights into its enhancement on secondary metabolism, which provides a reference for optimizing the production of secondary metabolites in actinomycetes.

Improving xylitol yield by deletion of endogenous xylitol-assimilating genes: a study of industrial Saccharomyces cerevisiae in fermentation of glucose and xylose.

Engineered Saccharomyces cerevisiae can reduce xylose to xylitol. However, in S.cerevisiae, there are several endogenous enzymes including xylitol dehydrogenase encoded by XYL2, sorbitol dehydrogenases encoded by SOR1/SOR2 and xylulokinase encoded by XKS1 may lead to the assimilation of xylitol. In this study, to increase xylitol accumulation, these genes were separately deleted through CRISPR/Cas9 system. Their effects on xylitol yield of an industrial S. cerevisiae CK17 overexpressing Candida tropicalis XYL1 (encoding xylose reductase) were investigated. Deletion of SOR1/SOR2 or XKS1 increased the xylitol yield in both batch and fed-batch fermentation with different concentrations of glucose and xylose. The analysis of the transcription level of key genes in the mutants during fed-batch fermentation suggests that SOR1/SOR2 are more crucially responsible for xylitol oxidation than XYL2 under the genetic background of S.cerevisiae CK17. The deletion of XKS1 gene could also weaken SOR1/SOR2 expression, thereby increasing the xylitol accumulation. The XKS1-deleted strain CK17ΔXKS1 produced 46.17 g/L of xylitol and reached a xylitol yield of 0.92 g/g during simultaneous saccharification and fermentation (SSF) of pretreated corn stover slurry. Therefore, the deletion of XKS1 gene provides a promising strategy to meet the industrial demands for xylitol production from lignocellulosic biomass.

Different transcriptional responses of haploid and diploid S. cerevisiae strains to changes in cofactor preference of XR.

BACKGROUND: Xylitol accumulation is a major barrier for efficient ethanol production through heterologous xylose reductase-xylitol dehydrogenase (XR-XDH) pathway in recombinant Saccharomyces cerevisiae. Mutated NADH-preferring XR is usually employed to alleviate xylitol accumulation. However, it remains unclear how mutated XR affects the metabolic network for xylose metabolism. In this study, haploid and diploid strains were employed to investigate the transcriptional responses to changes in cofactor preference of XR through RNA-seq analysis during xylose fermentation. RESULTS: For the haploid strains, genes involved in xylose-assimilation (XYL1, XYL2, XKS1), glycolysis, and alcohol fermentation had higher transcript levels in response to mutated XR, which was consistent with the improved xylose consumption rate and ethanol yield. For the diploid strains, genes related to protein biosynthesis were upregulated while genes involved in glyoxylate shunt were downregulated in response to mutated XR, which might contribute to the improved yields of biomass and ethanol. When comparing the diploids with the haploids, genes involved in glycolysis and MAPK signaling pathway were significantly downregulated, while oxidative stress related transcription factors (TFs) were significantly upregulated, irrespective of the cofactor preference of XR. CONCLUSIONS: Our results not only revealed the differences in transcriptional responses of the diploid and haploid strains to mutated XR, but also provided underlying basis for better understanding the differences in xylose metabolism between the diploid and haploid strains.

Effect of the TetR family transcriptional regulator Sp1418 on the global metabolic network of Saccharopolyspora pogona.

BACKGROUND: Saccharopolyspora pogona is a prominent industrial strain due to its production of butenyl-spinosyn, a high-quality insecticide against a broad spectrum of insect pests. TetR family proteins are diverse in a tremendous number of microorganisms and some are been researched to have a key role in metabolic regulation. However, specific functions of TetR family proteins in S. pogona are yet to characterize. RESULTS: In the present study, the overexpression of the tetR-like gene sp1418 in S. pogona resulted in marked effects on vegetative growth, sporulation, butenyl-spinosyn biosynthesis, and oxidative stress. By using qRT-PCR analysis, mass spectrometry, enzyme activity detection, and sp1418 knockout verification, we showed that most of these effects could be attributed to the overexpression of Sp1418, which modulated enzymes related to the primary metabolism, oxidative stress and secondary metabolism, and thereby resulted in distinct growth characteristics and an unbalanced supply of precursor monomers for butenyl-spinosyn biosynthesis. CONCLUSION: This study revealed the function of Sp1418 and enhanced the understanding of the metabolic network in S. pogona, and provided insights into the improvement of secondary metabolite production.

Identification of Novel Butyrate- and Acetate-Oxidizing Bacteria in Butyrate-Fed Mesophilic Anaerobic Chemostats by DNA-Based Stable Isotope Probing.

Butyrate is one of the most important intermediates during anaerobic digestion of protein wastewater, and its oxidization is considered as a rate-limiting step during methane production. However, information on syntrophic butyrate-oxidizing bacteria (SBOB) is limited due to the difficulty in isolation of pure cultures. In this study, two anaerobic chemostats fed with butyrate as the sole carbon source were operated at different dilution rates (0.01/day and 0.05/day). Butyrate- and acetate-oxidizing bacteria in both chemostats were investigated, combining DNA-Stable Isotope Probing (DNA-SIP) and 16S rRNA gene high-throughput sequencing. The results showed that, in addition to known SBOB, Syntrophomonas, other species of unclassified Syntrophomonadaceae were putative butyrate-oxidizing bacteria. Species of Mesotoga, Aminivibrio, Acetivibrio, Desulfovibrio, Petrimonas, Sedimentibacter, unclassified Anaerolineae, unclassified Synergistaceae, unclassified Spirochaetaceae, and unclassified bacteria may contribute to acetate oxidation from butyrate metabolism. Among them, the ability of butyrate oxidation was unclear for species of Sedimentibacter, unclassified Synergistaceae, unclassified Spirochaetaceae, and unclassified bacteria. These results suggested that more unknown species participated in the degradation of butyrate. However, the corresponding function and pathway for butyrate or acetate oxidization of these labeled species need to be further investigated.

Comparative transcriptomes reveal novel evolutionary strategies adopted by Saccharomyces cerevisiae with improved xylose utilization capability.

Production of ethanol from xylose by recombinant Saccharomyces cerevisiae is suboptimal with slow fermentation rate, compared with that from glucose. In this study, a strain-expressing Scheffersomyces stipitis xylose reductase-xylitol dehydrogenase (XR-XDH) pathway was subjected to adaptive evolution on xylose; this approach generated populations with the significantly improved cell growth and ethanol production rate. Mutants were isolated, and the best one was used for sporulation to generate eight stable mutant strains with improved xylose fermentation ability. They were used in a microarray assay to study the molecular basis of the enhanced phenotype. The enriched transcriptional differences among the eight mutant strains and the native strain revealed novel responses to xylose, which likely contributes to the improved xylose utilization. The upregulated vitamin B1 and B6 biosynthesis indicated that thiamine served as an important cofactor in xylose metabolism and may alleviate the redox stress. The increased expression of genes involved in sulfur amino acid biosynthesis and the decreased expression of genes related to Fe(II) transport may alleviate redox stress as well. Meanwhile, it was remarkable that several glucose-repressible genes, including genes of the galactose metabolism, gluconeogenesis, and ethanol catabolism, had a lower expression level after adaptive evolution. Concomitantly, the expression levels of two regulators of the glucose signaling pathway, Rgs2 and Sip4, decreased, indicating a reshaped signaling pathway to xylose after adaptive evolution. Our findings provide new targets for construction of a superior bioethanol producing strain through inverse metabolic engineering.

Transcriptome changes in adaptive evolution of xylose-fermenting industrial Saccharomyces cerevisiae strains with δ-integration of different xylA genes.

It is of utmost importance to construct industrial xylose-fermenting Saccharomyces cerevisiae strains for lignocellulosic bioethanol production. In this study, two xylose isomerase-based industrial S. cerevisiae strains, O7 and P5, were constructed by δ-integration of the xylose isomerase (XI) gene xylA from the fungus Orpinomyces sp. and from the bacterium Prevotella ruminicola, respectively. The xylose consumption of the strains O7 and P5 at 48-h fermentation was 17.71 and 26.10 g/L, respectively, in synthetic medium with xylose as the sole sugar source. Adaptive evolution further improved the xylose fermentation capacity of the two strains to 51.0 and 28.9% in average, respectively. The transcriptomes of these two strains before and after evolution were analyzed using RNA-Seq. The expression levels of the genes involved in cell integrity, non-optimal sugar utilization, and stress response to environment were significantly up-regulated after evolution and did not depend on the origin of xylA; the expression levels of the genes involved in transmembrane transport, rRNA processing, cytoplasmic translation, and other processes were down-regulated. The expression of genes involved in central carbon metabolism was fine-tuned after the evolution. The analysis of transcription factors (TFs) indicated that most of the genes with significant differential expression were regulated by the TFs related to cell division, DNA damage response, or non-optimal carbon source utilization. The results of this study could provide valuable references for the construction of efficient xylose-fermenting XI strains.

Does body mass index influence the outcome of midurethral sling procedures for stress urinary incontinence?

INTRODUCTION AND HYPOTHESIS: Whether midurethral sling (MUS) procedures are as effective in obese women as they are in women of normal weight is still a matter of controversy. The objective of this study was to determine if body mass index (BMI) influences the outcome of MUS procedures for stress urinary incontinence (SUI). METHODS: We searched electronic databases including EMBASE, MEDLINE, Web of Science and Ovid evidence-based medicine reviews to identify studies that explored the association between BMI and outcomes of MUS procedures. The studies were rated using the Newcastle-Ottawa scale; the meta-analysis was performed using Review Manager 5.3 software. RESULTS: This review included 11 studies, 6 prospective cohort studies and 5 retrospective studies, with a total of 2,846 patients. The objective success rates of MUS in patients with BMI >25 kg/m2 (overweight and obese) were lower than in patients with BMI 18.5 - <25 kg/m2 (normal weight; RR = 0.93, 95 % CI 0.89 - 0.97; P = 0.002). The objective success rates were not significantly different between the overweight group (BMI 25 - <30 kg/m2) and the obese group (BMI ≥30 kg/m2; RR = 0.95, 95 % CI 0.89 - 1.01; P = 0.08). There were no significant differences in subjective outcomes among the different BMI groups: BMI ≥25 kg/m2 versus 18.5 - <25 kg/m2 (RR = 1.03, 95 % CI 0.97 - 1.10; P = 0.29), and BMI ≥30 kg/m2 versus 25 - <30 kg/m2 (RR = 0.98, 95 % CI 0.92 - 1.04; P = 0.55). CONCLUSIONS: The objective success rates of MUS were lower in overweight and obese patients; however, the subjective outcomes of MUS were not significantly different among normal weight, overweight and obese patients. The MUS procedure is as effective in obese women as in women of normal weight, and therefore surgeons should not consider BMI >25 kg/m2 as a risk factor when discussing the suitability of the MUS procedure in a patient with SUI.

Generation of a monoclonal antibody specific to a new candidate tumor suppressor, cell adhesion molecule 2.

Cell adhesion molecule 2 (CADM2) is an immunoglobulin (Ig)-like cell adhesion molecule, which belongs to the CADMs family. The four members of CADMs family including three Ig-like domains and a short cytoplasmic tail share high degree of identity with each other, making it difficult to specifically identify each members using western blotting or immunohistochemistry. And most of anti-CADM2 antibodies available commercially or used in published papers are rabbit polyclonal antibodies, exhibiting nonspecific recognition in studies. In this study, we developed a monoclonal antibody (mAb) specific to an epitope on the extracellular domain of CADM2 using conventional hybridoma technology. Western blot assays indicated that the established mAb, named as 2B11, was specific for CADM2 recognition without interference of other members of CADMs family. Furthermore, 2B11 was competent to detect CADM2 expression specifically on the surface membranes of several types of tumor tissues, avoiding the false results with the polyclonal antibodies due to nonspecific staining. In conclusion, the mAb 2B11 could be suitable for specific detection of CADM2 expression in tumor cells or tissues.