Soluble expression of hMYDGF was improved by strain engineering and optimizations of fermentation strategies in Escherichia coli.

Myeloid-derived growth factor (MYDGF) is a cytokine that exhibits a variety of biological functions. This study focused on utilizing BL21(DE3) strain engineering and fermentation strategies to achieve high-level expression of soluble human MYDGF (hMYDGF) in Escherichia coli. Initially, the E. coli expressing strain BL21(DE3) was engineered by deleting the IpxM gene and inserting the GROEL/S and Trigger factor genes. The engineered E. coli strain BL21(TG)/pT-MYDGF accumulated 3557.3 ± 185.6 µg/g and 45.7 ± 6.7 mg/L of soluble hMYDGF in shake flask fermentation, representing a 15.6-fold increase compared to the control strain BL21(DE3)/pT-MYDGF. Furthermore, the yield of hMYDGF was significantly enhanced by optimizing the fermentation conditions. Under optimized conditions, the 5L bioreactor yielded up to 2665.8 ± 164.3 µg/g and 407.6 ± 42.9 mg/L of soluble hMYDGF. The results indicate that the implementation of these optimization strategies could enhance the ratio and yield of soluble proteins expressed by E.coli, thereby meeting the demands of industrial production. This study employed sophisticated strategies to lay a solid foundation for the industrial application of hMYDGF.

Efficacy of the combination of Chinese herbal medicine and negative pressure wound therapy in the treatment of patients with diabetic foot ulcer: A meta-analysis.

This study aimed to systematically evaluate the clinical efficacy of Chinese herbal medicine combined with negative pressure wound therapy (NPWT) in the treatment of diabetic foot ulcers (DFU). Computerised searches of the China National Knowledge Infrastructure, Wanfang, Chinese BioMedical Literature Database, PubMed, Cochrane Library and Embase databases were conducted for randomised controlled trials on the use of Chinese herbal medicines combined with NPWT for the treatment of DFU. The search period ranged from the time of establishment of each database to July 2023. Literature screening and data extraction were performed independently by two investigators, and the quality of the included studies was assessed. The meta-analysis was performed using Review Manager 5.4 software. A total of 25 studies were analysed, including 1777 DFUs, with 890 and 887 patients in the experimental and control groups, respectively. The results showed that the treatment of DFUs with a Chinese herbal medicine in combination with NPWT increased the overall effectiveness (odds ratio [OR] = 4.32, 95% confidence interval [CI]: 2.96-6.30, p < 0.001), wound healing rate (mean difference [MD] = 18.35, 95% CI: 13.07-23.64, p < 0.001) and ankle brachial index (MD = 0.10, 95% CI: 0.06-0.14, p < 0.001); reduced the wound healing time (MD = -11.01, 95% CI: -13.25 to -8.78, p < 0.001) and post-treatment wound area (MD = -1.73, 95% CI: -2.46 to -1.01, p < 0.001); decreased the C-reactive protein level (MD = -3.57, 95% CI: -5.13 to -2.00, p < 0.001); and increased vascular endothelial growth factor level (MD = 19.20, 95% CI: 8.36-30.05, p < 0.001). Thus, Chinese herbal medicines combined with NPWT can effectively promote wound healing, reduce inflammation and shorten the disease course in patients with DFU, while demonstrating precise clinical efficacy.

Systematic dissection of genomic features determining the vast diversity of conotoxins.

BACKGROUND: Conus, a highly diverse species of venomous predators, has attracted significant attention in neuroscience and new drug development due to their rich collection of neuroactive peptides called conotoxins. Recent advancements in transcriptome, proteome, and genome analyses have facilitated the identification of conotoxins within Conus' venom glands, providing insights into the genetic features and evolutionary patterns of conotoxin genes. However, the underlying mechanism behind the extraordinary hypervariability of conotoxins remains largely unknown. RESULTS: We analyzed the transcriptomes of 34 Conus species, examining various tissues such as the venom duct, venom bulb, and salivary gland, leading to the identification of conotoxin genes. Genetic variation analysis revealed that a subset of these genes (15.78% of the total) in Conus species underwent positive selection (Ka/Ks > 1, p < 0.01). Additionally, we reassembled and annotated the genome of C. betulinus, uncovering 221 conotoxin-encoding genes. These genes primarily consisted of three exons, with a significant portion showing high transcriptional activity in the venom ducts. Importantly, the flanking regions and adjacent introns of conotoxin genes exhibited a higher prevalence of transposon elements, suggesting their potential contribution to the extensive variability observed in conotoxins. Furthermore, we detected genome duplication in C. betulinus, which likely contributed to the expansion of conotoxin gene numbers. Interestingly, our study also provided evidence of introgression among Conus species, indicating that interspecies hybridization may have played a role in shaping the evolution of diverse conotoxin genes. CONCLUSIONS: This study highlights the impact of adaptive evolution and introgressive hybridization on the genetic diversity of conotoxin genes and the evolution of Conus. We also propose a hypothesis suggesting that transposable elements might significantly contribute to the remarkable diversity observed in conotoxins. These findings not only enhance our understanding of peptide genetic diversity but also present a novel approach for peptide bioengineering.

Ecotoxicological risk of antibiotics and their mixtures to aquatic biota with the DGT technique in sediments.

Antibiotics are emerging contaminants and widely used in human healthcare, livestock, and aquaculture. The toxicity posed by antibiotics and their mixtures in sediments depends on their bioavailability. Now, the bioavailability of organic materials can be determined accurately by the diffusive gradients in thin films (DGT) technique. This technique was used for the first time ever in this study to evaluate in detail the integral toxicity of antibiotics in sediments to aquatic biota. Zhelin Bay was selected as a case study, because it is the largest mariculture area in eastern Guangdong, South China. Two antibiotics, chlortetracycline (CTC) (A) and sulfachlorpyridazine (SCP), were detected at average concentrations of 2.83 and 1.14 ng/ml, respectively. The other fifteen antibiotics were undetectable. The single risk assessment based on the risk quotient (RQ) of CTC and SCP shows that a relatively low risk has occurred. After this careful assessment of probabilistic ecotoxicological risks, the combined toxicity of antibiotic mixtures (CTC and SCP) clearly indicates that the toxicity probability of surface sediments to aquatic organisms was relatively low (0.23%).

Liraglutide Alleviates Cognitive Deficit in db/db Mice: Involvement in Oxidative Stress, Iron Overload, and Ferroptosis.

Studies have shown that diabetes is associated with the occurrence of neurodegenerative diseases and cognitive decline. However, there is currently no effective treatment for diabetes-induced cognitive dysfunction. The superior efficacy of liraglutide (LIRA) for cognitive impairment and numerous neurodegenerative diseases has been widely demonstrated. This study determined the effects of LIRA on diabetic cognitive impairment and on the levels of oxidative stress, lipid peroxidation, iron metabolism and ferroptosis in the hippocampus. Mice were injected daily with liraglutide (200 µg/kg/d) for 5 weeks. LIRA could repair damaged neurons and synapses, and it increased the protein expression levels of PSD 95, SYN, and BDNF. Furthermore, LIRA significantly decreased oxidative stress and lipid peroxidation levels by downregulating the production of ROS and MDA and upregulating SOD and GSH-Px in the serum and hippocampus, and the upregulation of SOD2 expression was also proven. The decreased levels of TfR1 and the upregulation of FPN1 and FTH proteins observed in the LIRA-treated db/db group were shown to reduce iron overload in the hippocampus, whereas the increased expression of Mtft and decreased expression of Mfrn in the mitochondria indicated that mitochondrial iron overload was ameliorated. Finally, LIRA was shown to prevent ferroptosis in the hippocampus by elevating the expression of GPX4 and SLC7A11 and suppressing the excessive amount of ACSL4; simultaneously, the damage to the mitochondria observed by TEM was also repaired. For the first time, we proved in the T2DM model that ferroptosis occurs in the hippocampus, which may play a role in diabetic cognitive impairment. LIRA can reduce oxidative stress, lipid peroxidation and iron overload in diabetic cognitive disorders and further inhibit ferroptosis, thereby weakening the damage to hippocampal neurons and synaptic plasticity and ultimately restoring cognitive function.

TRIM65 triggers ß-catenin signaling via ubiquitylation of Axin1 to promote hepatocellular carcinoma.

Deregulation of ubiquitin ligases contributes to the malignant progression of human cancers. Tripartite motif-containing protein 65 (TRIM65) is an E3 ubiquitin ligase and has been implicated in human diseases, but its role and clinical significance in hepatocellular carcinoma (HCC) remain unknown. Here, we showed that TRIM65 expression was increased in HCC tissues and associated with poor outcome in two independent cohorts containing 888 patients. In vitro and in vivo data demonstrated that overexpression of TRIM65 promoted cell growth and tumor metastasis, whereas knockdown of TRIM65 resulted in opposite phenotypes. Further studies revealed that TRIM65 exerted oncogenic activities via ubiquitylation of Axin1 to activate the ß-catenin signaling pathway. TRIM65 directly bound to Axin1 and accelerated its degradation through ubiquitylation. Furthermore, HMGA1 was identified as an upstream regulator of TRIM65 in HCC cells. In clinical samples, TRIM65 expression was positively correlated with the expression of HMGA1 and nuclear ß-catenin. Collectively, our data indicate that TRIM65 functions as an oncogene in HCC. The newly identified HMGA1/TRIM65/ß-catenin axis serves as a promising prognostic factor and therapeutic target.

SPAG5 interacts with CEP55 and exerts oncogenic activities via PI3K/AKT pathway in hepatocellular carcinoma.

BACKGROUND: Deregulation of microtubules and centrosome integrity is response for the initiation and progression of human cancers. Sperm-associated antigen 5 (SPAG5) is essential for the spindle apparatus organization and chromosome segregation, but its role in hepatocellular carcinoma (HCC) remains undefined. METHODS: The expression of SPAG5 in HCC were examined in a large cohort of patients by RT-PCR, western blot and IHC. The clinical significance of SPAG5 was next determined by statistical analyses. The biological function of SPAG5 in HCC and the underlying mechanisms were investigated, using in vitro and in vivo models. RESULTS: Here, we demonstrated that SPAG5 exhibited pro-HCC activities via the activation of PI3K/AKT signaling pathway. SPAG5 expression was increased in HCC and correlated with poor outcomes in two independent cohorts containing 670 patients. High SPAG5 expression was associated with poor tumor differentiation, larger tumor size, advanced TNM stage, tumor vascular invasion and lymph node metastasis. In vitro and in vivo data showed that SPAG5 overexpression promoted tumor growth and metastasis, whereas SPAG5 knockdown led to the opposite phenotypes. SPAG5 interacted with centrosomal protein CEP55 to trigger the phosphorylation of AKT at Ser473. Inhibition of PI3K/AKT signaling markedly attenuated SPAG5-mediated cell growth. Furthermore, SPAG5 expression was suppressed by miR-363-3p which inhibited the activity of SPAG5 mRNA 3'UTR. Ectopic expression of SPAG5 partly abolished the miR-363-3p-caused cell cycle arrest and suppression of cell proliferation and migration. CONCLUSIONS: Collectively, these findings indicate that SPAG5 serves a promising prognostic factor in HCC and functions as an oncogene via CEP55-mediated PI3K/AKT pathway. The newly identified miR-363-3p/SPAG5/CEP55 axis may represent a potential therapeutic target for the clinical intervention of HCC.

Cultivation of seaweed Gracilaria lemaneiformis enhanced biodiversity in a eukaryotic plankton community as revealed via metagenomic analyses.

Plankton diversity reflects the quality and health of waters and should be monitored as a critical feature of marine ecosystems. This study applied a pair of 28S rRNA gene-specific primers and pyrosequencing to assess the effects of large-scale cultivation of the seaweed Gracilaria lemaneiformis on the biodiversity of eukaryotic plankton community in the coastal water of Guangdong, China. With 1 million sequences (2,221 operational taxonomic units [OTUs]) obtained from 51 samples, we found that the biodiversity of eukaryotic plankton community was significantly higher in the seaweed cultivation area than that in the nearby control area as reflected in OTU richness, evenness (Shannon-Wiener index) and dominance (Simpson index) for total plankton community and its four subcategories when Gracilaria biomass reached the maximum, while no such a significant difference was observed before seaweed inoculation. Our laboratory experiment using an artificial phytoplankton community of nine species observed the same effects of Gracilaria exposure. Principal component analysis and principal coordinates analysis showed the plankton community structure in cultivation area markedly differed from the control area when Gracilaria biomass reached its maximum. Redundancy analysis showed that G. lemaneiformis was the critical factor in controlling the dynamics of eukaryotic plankton communities in the studied coastal ecosystem. Our results explicitly demonstrated G. lemaneiformis cultivation could enhance biodiversity of plankton community via allelopathy, which prevents one or several plankton species from blooming and consequently maintains a relatively higher biodiversity. Our study provided further support for using large-scale G. lemaneiformis cultivation as an effective approach for improving costal ecosystem health.

Prognostic factors of regression and relapse of complex atypical hyperplasia and well-differentiated endometrioid carcinoma with conservative treatment.

OBJECTIVE: To evaluate possible prognostic factors regarding regression and relapse of complex atypical hyperplasia (CAH) and well-differentiated endometrioid adenocarcinoma (WDC) treated with conservative treatment. METHODS: The retrospective study reviewed clinicopathologic, treatment, regression and relapse data from patients diagnosed with CAH or WDC who were treated with conservative treatment at 4 institutions. Potential factor evaluation was performed. SPSS 16 was used for statistical analyses. RESULTS: Eighty-eight patients were included (51 had WDC, and 37 had CAH). Regression was evaluated in 88 patients, with a median follow-up of 61 (range 15-95) months. Seventy-seven (87.5%) patients regressed, and 11 (12.5%) had persistent or progressive disease. Univariate and multivariate analyses showed no factors associated with regression. Relapse was evaluated in 71 patients, with median follow-up of 54 (range 8-86) months. Twenty-five/71 (35.2%) patients experienced relapse. On univariate analysis, body mass index (BMI) 30 or higher (p=0.001), WCD at initial biopsy (p=0.017) and positive expression of post-treatment ki67 (p=0.033) were associated to a higher relapse probability. However, only BMI 30 or higher was significant on multivariate analysis (p=0.012). The Kaplan-Meier analysis revealed a higher relapse probability in the patients with BMI 30 or higher (p=0.001). CONCLUSION: Obesity seems to be a risk factor for relapse of CAH or WDC with conservative treatment.

Toxic effects of triclosan on the detoxification system and breeding of Daphnia magna.

The toxic effects of different concentrations of Triclosan (TCS) (1-128 µg/L) on Daphnia magna (D. magna) were investigated by acute (48 h) and chronic (21-day) toxicity tests. The response of antioxidase system and Phase I metabolism process of D. magna exposed to TCS were investigated by measuring a series of biomarkers including glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), 7-ethoxyresorufin O-deethylase (EROD), Erythromycin N-demethylase (ERND) and Aminopyrine N-demethylase (APND). The 48 h LC50 of TCS was 330 µg/L for D. magna. In the chronic test, total number of neonates per female, body length and the intrinsic rate of natural increase (r) of D. magna increased at the low exposure concentrations (1-16 µg/L) and decreased at the high concentrations (64-128 µg/L), while the total number of molting per adult decreased continually. The GST and CAT activities showed no significant increase in all treatments, and SOD activities were induced after 24-h exposure and inhibited after 48-h exposure at 4-128 µg/L of concentrations. The MDA content increased after 6-h exposure but decreased after 48-h exposure at 4-128 µg/L. EROD activities initially increased after 6-h exposure, but decreased after 24 and 48-h exposure, ERND and APND activities showed a similar temporal pattern among different treatments groups. SOD, MDA and APND were sensitive to TCS, thus they are suitable as potential biomarkers for the exposure to TCS.

Metabolic engineering and pathway construction for O-acetyl-L-homoserine production in Escherichia coli.

O-Acetyl-L-homoserine (OAH) is a potentially important platform metabolic intermediate for the production of homoserine lactone, methionine, 1,4-butanediol and 1,3-propanediol which have giant market value. Currently, multiple strategies have been adopted to explore sustainable production of OAH. However, the production of OAH by consuming cheap bio-based feedstocks with Escherichia coli as the chassis is still in its infancy. Construction of high yield OAH-producing strains is of great significance in industry. In this study, we introduced an exogenous metA from Bacillus cereus (metXbc) and engineered an OAH-producing strain by combinatorial metabolic engineering. Initially, exogenous metXs/metA were screened and used to reconstruct an initial biosynthesis pathway of OAH in E. coli. Subsequently, the disruption of degradation and competitive pathways combined with optimal expression of metXbc were carried out, accumulating 5.47 g/L OAH. Meanwhile, the homoserine pool was enriched by overexpressing metL with producing 7.42 g/L OAH. Lastly, the carbon flux of central carbon metabolism was redistributed to balance the metabolic flux of homoserine and acetyl coenzyme A (acetyl-CoA) in OAH biosynthesis with accumulating 8.29 g/L OAH. The engineered strain produced 24.33 g/L OAH with a yield of 0.23 g/g glucose in fed-batch fermentation. By these strategies, the key nodes for OAH synthesis were clarified and corresponding strategies were proposed. This study would lay a foundation for OAH bioproduction. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03564-5.

Utilization of lipidic food waste as low-cost nutrients for enhancing the potentiality of biofuel production from engineered diatom under temperature variations.

The scarcity of natural fossil fuels presents a promising opportunity for the development of renewable microalgae-based biofuels. However, the current microalgae cultivation is unable to effectively address the high costs of the production of biofuels. To tackle this challenge, this study focused on recruiting engineered Phaeodactylum tricornutum (FabG-OE) to enhance biomass accumulation and lipid production by employing food waste hydrolysate under temperature variations. The biomass and lipid accumulations of FabG-OE were improved effectively in mixed culture medium and food waste hydrolysate at a volume ratio (v/v) of 80:20 at 30 °C. It was found that oxidative stress might contribute to the overexpression of lipogenic genes, thereby leading to lipogenesis at 30 °C. Upscaling cultivation of FabG-OE at 30 °C using a semi-continuous strategy and batch strategy was conducted to achieve 0.73 and 0.77 g/L/d of biomass containing 0.35 and 0.38 g/L/d of lipid, respectively. In summary, these findings provide valuable insights for advancing microalgae-based biofuel production.

Effects of liraglutide on astrocyte polarization and neuroinflammation in db/db mice: focus on iron overload and oxidative stress.

Neuroinflammation plays a crucial role in the occurrence and development of cognitive impairment in type 2 diabetes mellitus (T2DM), but the specific injury mechanism is not fully understood. Astrocyte polarization has attracted new attention and has been shown to be directly and indirectly involved in neuroinflammation. Liraglutide has been shown to have beneficial effects on neurons and astrocytes. However, the specific protection mechanism still needs to be clarified. In this study, we assessed the levels of neuroinflammation and A1/A2-responsive astrocytes in the hippocampus of db/db mice and examined their relationships with iron overload and oxidative stress. First, in db/db mice, liraglutide alleviated the disturbance of glucose and lipid metabolism, increased the postsynaptic density, regulated the expression of NeuN and BDNF, and partially restored impaired cognitive function. Second, liraglutide upregulated the expression of S100A10 and downregulated the expression of GFAP and C3, and decreased the secretion of IL-1ß, IL-18, and TNF-α, which may confirm that it regulates the proliferation of reactive astrocytes and A1/A2 phenotypes polarize and attenuate neuroinflammation. In addition, liraglutide reduced iron deposition in the hippocampus by reducing the expression of TfR1 and DMT1 and increasing the expression of FPN1; at the same time, liraglutide by up-regulating the levels of SOD, GSH, and SOD2 expression, as well as downregulation of MDA levels and NOX2 and NOX4 expression to reduce oxidative stress and lipid peroxidation. The above may attenuate A1 astrocyte activation. This study preliminarily explored the effect of liraglutide on the activation of different astrocyte phenotypes and neuroinflammation in the hippocampus of a T2DM model and further revealed its intervention effect on cognitive impairment in diabetes. Focusing on the pathological consequences of astrocytes may have important implications for the treatment of diabetic cognitive impairment.

Attitudes and influencing factors associated with smoking cessation: An online cross-sectional survey in China.

INTRODUCTION: Quitting smoking, the critical path to reach the global targets of reducing tobacco use, can bring major and immediate health benefits to smokers. Exploring factors that help individuals to quit smoking is of great importance. The present study explored influencing factors on smoking cessation, in order to provide comprehensive reference for tobacco control policies. METHODS: Ex-smokers and current smokers were recruited online in this cross-sectional survey, from 1 October to 31 November 2022, in China. The observational data were collected using a questionnaire to collect information with respect to sociodemographic characteristics of smokers, attitudes towards smoking cessation, details of smoking cessation, and different potential factors related to smoking cessation through open-ended questions. RESULTS: A total of 638 smokers from 30 provinces were recruited as eligible respondents, with a mean age of 37.3 ± 11.7 years and a mean smoking history of 15.9 ± 13.7 years. The percentage of males was 92.3%. Of the 638 respondents, only 3.9% had no intention to stop smoking. Among 155 subjects who had quitted smoking successfully, willpower (55.5%) was considered as the most important contributing factor. Among 365 subjects who tried to quit but failed, lack of willpower (28.2%), tobacco dependence (16.2%), influence of surrounding smokers or smoking environments (15.9%), bad moods (9.9%), stress from work or life (7.9%), habits (7.1%), socialization (4.1%), and easy availability of tobacco (2.7%) were considered as the adverse factors leading to failure in quitting smoking. CONCLUSIONS: Willpower and support from family members were the vital factors that lead to successful smoking cessation. Future tobacco control policies should also focus on addressing withdrawal symptoms and creating smoke-free environments as well as other factors.

Bioremediation of Catechol and Concurrent Accumulation of Biocompounds by the Microalga Crypthecodinium cohnii.

Burgeoning commercial applications of catechol have led to its excessive accumulation in the environment, thereby posing a severe ecological threat. Bioremediation has emerged as a promising solution. The potential of the microalga Crypthecodinium cohnii to degrade catechol and use the byproduct as a carbon source was investigated in this study. Catechol significantly increased C. cohnii growth and was rapidly catabolized within 60 h of cultivation. Transcriptomic analysis highlighted the key genes involved in catechol degradation. Real-time polymerase chain reaction (RT-PCR) analysis showed that transcription of key genes CatA, CatB, and SaID involved in the ortho-cleavage pathway was remarkably increased by 2.9-, 4.2-, and 2.4- fold, respectively. Key primary metabolite content was also markedly altered, with a specific increment in polyunsaturated fatty acids. Electron microscopy and antioxidant analysis showed that C. cohnii could tolerate catechol treatment without morphological aberrations or oxidative stress. The findings provide a strategy for C. cohnii in the bioremediation of catechol and concurrent polyunsaturated fatty acids (PUFA) accumulation.

The Role of Iron Overload in Diabetic Cognitive Impairment: A Review.

It is well documented that diabetes mellitus (DM) is strongly associated with cognitive decline and structural damage to the brain. Cognitive deficits appear early in DM and continue to worsen as the disease progresses, possibly due to different underlying mechanisms. Normal iron metabolism is necessary to maintain normal physiological functions of the brain, but iron deposition is one of the causes of some neurodegenerative diseases. Increasing evidence shows that iron overload not only increases the risk of DM, but also contributes to the development of cognitive impairment. The current review highlights the role of iron overload in diabetic cognitive impairment (DCI), including the specific location and regulation mechanism of iron deposition in the diabetic brain, the factors that trigger iron deposition, and the consequences of iron deposition. Finally, we also discuss possible therapies to improve DCI and brain iron deposition.

Application of diffusive gradients in thin films to determine rare earth elements in surface sediments of Daya Bay, China: Occurrence, distribution and ecotoxicological risks.

Known as burgeoning contaminants, the bioavailability of rare earth elements (REEs) can be determined using diffusive gradients in thin films (DGT). As Daya Bay (South China) has been under serious anthropogenic influences, the present study examined the distribution of REEs in surface sediments and their possible ecological risks in the bay. The range of DGT-labile concentrations of REEs (∑REEs) was from 5.67 µg/L to 8.41 µg/L, with an average of 7.34 µg/L. Results of assessment of single REE toxicity revealed that the risk quotient (RQ) values of Y, Ce and Yb were >1, indicating that their potential negative impacts on the nearby environment. However, analysis of the integral toxicity of REE mixtures through assessment of probabilistic ecotoxicological risks showed that there was a negligibly low probability of toxicity of PRE surface sediments to aquatic organisms in the study area.

Rerouting Fluxes of the Central Carbon Metabolism and Relieving Mechanism-Based Inactivation of l-Aspartate-α-decarboxylase for Fermentative Production of ß-Alanine in Escherichia coli.

ß-Alanine, with the amino group at the ß-position, is an important platform chemical that has been widely applied in pharmaceuticals and feed and food additives. However, the current modest titer and productivity, increased fermentation cost, and complicated operation are the challenges for producing ß-alanine by microbial fermentation. In this study, a high-yield ß-alanine-producing strain was constructed by combining metabolic engineering, protein engineering, and fed-batch bioprocess optimization strategies. First, an aspartate-α-decarboxylase from Bacillus subtilis was introduced in Escherichia coli W3110 to construct an initial ß-alanine-producing strain. Production of ß-alanine was obviously increased to 4.36 g/L via improving the metabolic flux and reducing carbon loss by rerouting fluxes of the central carbon metabolism. To further increase ß-alanine production, mechanism-based inactivation of aspartate-α-decarboxylase was relieved by rational design to maintain the productivity at a high level in ß-alanine fed-batch fermentation. Finally, fed-batch bioprocess optimization strategies were used to improve ß-alanine production to 85.18 g/L with 0.24 g/g glucose yield and 1.05 g/L/h productivity in fed-batch fermentation. These strategies can be effectively used in the construction of engineered strains for ß-alanine and production of its derivatives, and the final engineered strain was a valuable microbial cell factory that can be used for the industrial production of ß-alanine.

Evaluation of risk factors and clinicopathologic features for intrahepatic cholangiocarcinoma in Southern China: a possible role of hepatitis B virus.

BACKGROUND: Recent efforts suggest an etiologic role of hepatitis B virus (HBV) infection in intrahepatic cholangiocarcinoma (ICC) and the involvement of hepatic progenitor cell in ICC development, without definitive conclusions. This case-control study was undertaken to investigate risk factors for ICC, and clinicopathological features of HBV-associated ICC were analyzed. METHODS: The report comprised 98 patients with pathologically confirmed ICC and 196 healthy control subjects. Logistic regression was used to determine odds ratios and 95% confidence intervals. The sex and age distributions of HBV-related and unrelated ICC patients were compared respectively with those of 882 HBV-associated hepatocellular carcinoma patients from a random selection, and the clinicopathological data of 62 ICC patients with or without HBV infection undergoing surgical resection were compared. RESULTS: There was an association between ICC and each of HBV infection, liver cirrhosis, hepatolithiasis, and liver fluke infestation with the odds ratios (95% confidence intervals) of 2.75 (1.27-5.95), 8.42 (2.50-28.37), 22.81 (7.16-72.68), and 3.55 (1.60-7.89), respectively, with a marked synergism of cirrhosis and HBV infection (20.67; 5.40-79.06). Compared with HBV-unrelated ICC patients, HBV-related ICC patients were more common in male and younger subjects, had a higher incidence of abnormal serum alfa-fetoprotein level, cirrhosis, and neutrophilic infiltration, and had a lower proportion of elevated carbohydrate antigen 19-9 (CA19-9) values. CONCLUSIONS: The independent association of HBV infection with ICC, synergy between cirrhosis and HBV infection, and some clinicopathological similarities between HBV-related ICC and hepatocellular carcinoma suggests that both may share similar or common tumorigenic process and may possibly originate from malignant transformation of hepatic progenitor cell.

Study on water quality and genotoxicity of surface microlayer and subsurface water in Guangzhou section of Pearl River.

In order to understand the water quality and the genotoxicity of various surfaces in the Guangzhou section of the Pearl River during January to December of 2008, we investigated and studied the current water situation of the surface microlayer (SML) and the subsurface water (SSW) in Guanzhou section (Zhongda Dock and Yuzhu Dock) of the Pearl River by chemical analysis and biological monitoring method (Vicia faba micronucleus test). The results showed that during these months concentrations of the indexes of the two docks water such as total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD) exceeded the national III level of surface water quality, and the indexes of SML were much higher than the ones of SSW (P< 0.05), and the exceeding rate of TN, TP of SML was 100%. According to the eutrophic evaluation standard, the water bodies of SML and SSW in the two docks were in a eutrophication during these months. The eutrophication and pollution of SML was more serious, and the highest index of eutrophication (E value) was up to 81.9, which also had obvious difference with COD and TP (P< 0.05). The water of SML in the two docks enriched to N, P, and chlorophyll a (Chl. a) seriously, and the enrichment factor of SML in Zhongda Dock to N, P, and Chl. a was 0.71 ∼ 2.78, 0.98 ∼ 1.18, and 0.49 ∼ 13.99, respectively, and the one in the Yuzhu Dock was 1.09 ∼ 1.52, 1 ∼ 1.14, and 0.72 ∼ 4.07, respectively. Through inspecting the water genotoxicity of various layers by V. faba micronucleus test, we could know that the average annual MCN ‰ of SML and SSW in the two docks was 6.09 ‰, 5.53 ‰, 5.57 ‰, and 5.249 ‰, respectively. In general, the above value of SML was a little higher than the one of SSW, but there was not a remarkable difference (P> 0.05). This research shows that the water quality in a medium to heavy eutrophication in the Guangzhou section of Pearl River belongs to national III ∼ IV level, and SML has the capability of enrichment to the pollutants such as N and P and induces the increase of micronucleus rate of V. faba tip cell. The study also indicates that there may be genotoxicity matters such as N, P in water body.