Secretory expression of amylosucrase in Bacillus licheniformis through twin-arginine translocation pathway.

Amylosucrase (EC 2.4.1.4) is a versatile enzyme with significant potential in biotechnology and food production. To facilitate its efficient preparation, a novel expression strategy was implemented in Bacillus licheniformis for the secretory expression of Neisseria polysaccharea amylosucrase (NpAS). The host strain B. licheniformis CBBD302 underwent genetic modification through the deletion of sacB, a gene responsible for encoding levansucrase that synthesizes extracellular levan from sucrose, resulting in a levan-deficient strain, B. licheniformis CBBD302B. Neisseria polysaccharea amylosucrase was successfully expressed in B. licheniformis CBBD302B using the highly efficient Sec-type signal peptide SamyL, but its extracellular translocation was unsuccessful. Consequently, the expression of NpAS via the twin-arginine translocation (TAT) pathway was investigated using the signal peptide SglmU. The study revealed that NpAS could be effectively translocated extracellularly through the TAT pathway, with the signal peptide SglmU facilitating the process. Remarkably, 62.81% of the total expressed activity was detected in the medium. This study marks the first successful secretory expression of NpAS in Bacillus species host cells, establishing a foundation for its future efficient production. ONE-SENTENCE SUMMARY: Amylosucrase was secreted in Bacillus licheniformis via the twin-arginine translocation pathway.

Investigation into the impact of proton pump inhibitors on sertraline transport across the blood-brain barrier.

As a widely used antidepressant that works by inhibiting the reuptake of serotonin, sertraline exerts an antidepressant effect depending on its concentration in the brain, which might be limited by the blood-brain barrier (BBB). It is highly possible to combine proton pump inhibitors (PPIs) with sertraline in clinical trials. Nevertheless, the role played by PPIs in regulating the transport of sertraline across the BBB remains unclear. Here, the impact of PPIs on the distribution of sertraline in the brain and the mechanisms involved were investigated. A mouse brain distribution study showed that Omeprazole (OME), Pantoprazole (PAN), Ilaprazole (ILA), and Esomeprazole (ESO) increased the area under the brain concentration-time curves (AUC) for sertraline by 2.02-, 3.18-, 3.04-, and 4.21-fold, respectively, after the 14-day administration of PPIs. Besides, PPIs significantly increased the permeability of sertraline in brain perfusion experiments, with PAN having the highest rank order, followed by ILA, OME, and ESO. In the tail suspension test (TST), co-administration PPI groups showed significantly shorter immobility time than the control group. In vitro, four PPIs inhibited sertraline efflux in breast cancer resistance protein (BCRP)-overexpressing MDCKII cells, and showed a mixed inhibition type. In this study, PPIs were further found to inhibit the mRNA and protein expression of brain BCRP. To sum up, the findings of this study revealed that PPIs could enhance the brain distribution and antidepressant effect of sertraline, which may be attributed to the inhibition of BCRP expression at the BBB by PPIs.

Change of sexual behavior among men who have sex with men before, during and after COVID-19 pandemic in China: a cross-sectional study.

INTRODUCTION: The COVID-19 epidemic control and prevention strategies affected people's sexual activities and behaviors. Little was known about long-term effects of COVID-19 prevention and control strategies on sexual behaviors among men who have sex with men (MSM). This study aimed to examine changes in risky sexual behaviors of MSM before and after the local epidemic. METHODS: An online survey was conducted nationwide from June 1 to June 10, 2022. MSM aged 16 years and above, residing in China were recruited through convenience sampling. A generalized estimating equation model with modified Poisson regression was used to analyze changes in multiple sexual partners, unprotected sex, mobility for sexual activity, and recreational substance use before and after the local epidemic. RESULTS: Compared to the pre-pandemic (36.5%), the prevalence of multiple sexual partners (11.5%) significantly decreased during the local epidemic and then increased after the local epidemic (25.2%) but remained lower than pre-pandemic, as did the prevalence of unprotected sex (31.1%, 19.4%, and 26.1%), mobility for sexual activity (7.5%, 2.8%, and 4.1%) and recreational substance use (47.7%, 27.2%, and 39.5%). Compared to the pre-pandemic, higher declines in the prevalence of risky sexual behaviors during the local epidemic existed among MSM living without a regular partner (44% decrease in unprotected sex and 46% in recreational substance use), with a bachelor's degree and above (70% decrease in multiple sex partners, 39% in unprotected sex, 67% in mobility for sexual activity and 44% in recreational substance use), higher incomes (70% decrease in multiple sex partners), self-identified gay or bisexual/unsure (38-71%), and HIV infection (49-83% decrease respectively in these four indicators). After the local epidemic, the declines in the above indicators compared to the pre-pandemic were correspondingly. And higher declines existed among MSM living without a regular partner (8% decrease in unprotected sex and 13% in recreational substance use), with a bachelor's degree and above (33% decrease in multiple sex partners), higher incomes (55% decrease in mobility for sexual activity), self-identified gay (51% decrease in mobility for sexual activity), and HIV infection (32%, 68%, 24% decrease respectively in unprotected sex, mobility for sexual activity and recreational substance use). CONCLUSIONS: Risky sexual behaviors reduced considerably during the local epidemic, then seemed rebounded after the outbreak but wouldn't return to pre-pandemic levels. More attention should be paid to vulnerable people with lower socio-economic status, HIV-positive, and sexual minorities for sustained HIV and COVID-19 prevention.

Etiological Study of Acute Conjunctivitis Caused by Human Adenovirus in Shanxi Province, China, between 2016 and 2019.

Human adenovirus (HAdV) is the primary cause of acute conjunctivitis. To improve our understanding of the etiology of adenoviral conjunctivitis, ocular samples were collected from 160 conjunctivitis cases in the Shanxi province of northern China between 2016 and 2019. Through preliminary identification, virus isolation, and type identification, a total of 63 HAdV isolates were obtained from the samples. Three species and seven types (HAdV-3, HAdV-4, HAdV-8, HAdV-37, HAdV-53, HAdV-64, and HAdV-85) were detected, with HAdV-64, HAdV-3, and HAdV-8 being the predominant types in 2016, 2018, and 2019, respectively. Further phylogenetic analysis indicated the relative genomic stability of seven HAdV-type strains, except for 4 HAdV-3 strains in 2018 with a novel amino acid insertion site (Pro) between P19 and S20 in the penton base gene. It is worth noting that the genomes of two Shanxi HAdV-85 strains from 2016 were almost identical to those of previously reported HAdV-85 strains that circulated in Japan in 2014 to 2018. China was the second country to sample and isolate HAdV-85, suggesting that HAdV-85 might be underreported as an ocular pathogen. Data obtained in this study provide valuable information on the prevalence of acute conjunctivitis caused by HAdV. IMPORTANCE HAdV types in cases of conjunctivitis in Shanxi province, China, in 2016 to 2019 showed evident diversity, with seven types (HAdV-3, HAdV-4, HAdV-8, HAdV-37, HAdV-53, HAdV-64, and HAdV-85) being identified, and relative genome stability of these viruses was observed. In addition, China was the second country to sample and isolate HAdV-85, which suggests that HAdV-85 might be underreported as an important pathogen associated with ocular infections. These results enhance the understanding of the etiology of adenoviral conjunctivitis and may aid in the development of prevention and control strategies for HAdV-related ocular infections in China.

Treatment failure and associated factors among people living with HIV on highly active antiretroviral therapy in mainland China: A systematic review and meta-analysis.

OBJECTIVE: Reducing the prevalence of treatment failure among people living with HIV (PLHIV) on highly active antiretroviral therapy (HAART) is crucial for improving individual health and reducing disease burden. This study aimed to assess existing evidence on treatment failure and its associated factors among PLHIV in mainland China. METHODS: We conducted a comprehensive search of PubMed, Web of Science, Cochrane Library, WanFang, China National Knowledge Infrastructure, and SinoMed databases. Relevant studies on treatment failure among PLHIV in mainland China until September 2022 were searched, including cross-sectional, case-control, and cohort studies. The primary outcome was treatment failure, and secondary outcomes were the potential influencing factors of treatment failure. We performed a meta-analysis to pool each outcome of interest, including meta-regression, subgroup, publication bias, and sensitivity analyses. RESULTS: A total of 81 studies were deemed eligible and included in the final meta-analysis. The pooled treatment failure prevalence among PLHIV in mainland China was 14.40% (95% confidence interval [CI]:12.30-16.63), of which the virological and immunological failure prevalence was 10.53% (95%CI:8.51-12.74) and 18.75% (95%CI:15.44-22.06), respectively. The treatment failure prevalence before and after 2016 was 18.96% (95%CI:13.84-24.67) and 13.19% (95%CI:10.91-15.64). Factors associated with treatment failure included good treatment adherence (odds ratio [OR] = 0.36, 95%CI:0.26-0.51), baseline CD4 counts>200 cells/µL (OR = 0.39, 95%CI:0.21-0.75), HAART regimens containing Tenofovir Disoproxil Fumarate (TDF) (OR = 0.70, 95%CI:0.54-0.92), WHO clinical stage III/IV (OR = 2.02, 95%CI:1.14-3.59) and age≥40 years (OR = 1.56, 95%CI:1.23-1.97). CONCLUSION: The prevalence of treatment failure among PLHIV receiving HAART in mainland China was low and tended to decline. Poor adherence, low baseline CD4 count, HAART regimens without TDF, advanced clinical stage, and old age were contributing factors for treatment failure. Relevant intervention programs are needed with increasing treatment adherence through behavioral intervention or precise intervention targeting older adults.

Excess mortality and associated factors among people living with HIV initiating highly active antiretroviral therapy in Luzhou, China 2006-2020.

BACKGROUND: To estimate crude mortality, excess mortality, and standardized mortality rates (SMR) among people living with HIV (PLHIV) initiating highly active antiretroviral therapy (HAART) in Luzhou, China 2006-2020, and assess associated factors. METHODS: PLHIV initiating HAART in the HIV/AIDS Comprehensive Response Information Management System (CRIMS) in Luzhou, China 2006-2020 were included in the retrospective cohort study. The crude mortality, excess mortality, and SMR were estimated. Multivariable Poisson regression model was used for analyzing risk factors associated with excess mortality rates. RESULTS: The median age among 11,468 PLHIV initiating HAART was 54.5 years (IQR:43.1-65.2). The excess mortality rate decreased from 1.8 deaths/100 person-years (95% confidence interval [CI]:1.4-2.4) in 2006-2011 to 0.8 deaths/100 person-years (95%CI:0.7-0.9) in 2016-2020. SMR decreased from 5.4 deaths/100 person-years (95%CI:4.3-6.8) to 1.7 deaths/100 person-years (95%CI:1.5-1.8). Males had greater excess mortality with the eHR of 1.6 (95%CI:1.2-2.1) than females. PLHIV with CD4 counts ≥ 500 cells/µL had the eHR of 0.3 (95%CI:0.2-0.5) in comparison to those with CD4 counts < 200 cells/µL. PLHIV with WHO clinical stages III/IV had greater excess mortality with the eHR of 1.4 (95%CI:1.1-1.8). PLHIV with time from diagnosis to HAART initiation ≤ 3 months had the eHR of 0.7 (95%CI:0.5-0.9) compared to those with time ≥ 12 months. PLHIV with initial HAART regimens unchanged and viral suppression had the eHR of 1.9 (95%CI:1.4-2.6) and 0.1 (95%CI:0.0-0.1), respectively. CONCLUSIONS: The excess mortality and SMR among PLHIV initiating HAART in Luzhou, China decreased substantially from 2006 to 2020, but the mortality rate among PLHIV was still higher than general population. PLHIV who were male, with baseline CD4 counts less than 200 cells/µL, WHO clinical stages III/IV, time from diagnosis to HAART initiation ≥ 12 months, initial HAART regimens unchanged, and virological failure had a greater risk of excess deaths. Early and efficient HAART would be significant in reducing excess mortality among PLHIV.

Sexual Behavior and Perceived Loneliness in Elderly People Living with HIV in China during the COVID-19 Pandemic.

BACKGROUND: The proportion of elderly people living with HIV (PLHIV) is increasing in China. To advance targeted interventions and substantially improve their quality of life, we investigate indicators of loneliness and sexual behavior among elderly PLHIV in 10 districts/counties in China during the COVID-19 pandemic. METHODS: The demographic information and laboratory test results of the potential respondents were initially collected from the China Information System for Disease Control and Prevention. A two-stage stratified cluster sampling was used. The questionnaire survey was individually provided to all PLHIV aged +60. RESULTS: We recruited 1017 valid respondents with a median age of 66 years (interquartile range of 63-71), of which 776 (76.3%) were male. Overall, 341 respondents (33.5%) lived alone, and 304 (29.9%) felt lonely. A total of 726 respondents (71.4%) informed others of their HIV diagnosis. Among the 726 respondents, children were the most common group with whom the older people shared their HIV infection status, accounting for 82.9%. Approximately 20% of the older PLHIV engaged in sexual behavior in the last year, and 70% reported not using condoms. A significantly greater risk of loneliness was found among the females (AOR = 1.542, CI: 1.084, 2.193), those who suffered discrimination from informed people (AOR = 4.719, CI: 2.986, 7.459), were diagnosed <1 year prior (AOR = 2.061, CI: 1.345, 3.156), those living alone (AOR = 2.314, CI: 1.632, 3.280), those having no friends (AOR = 1.779, CI: 1.327, 2.386), and those who had a divorced or widowed marital status (AOR = 1.686, CI: 1.174, 2.421). CONCLUSIONS: Compared with non-lonely participants, the lonely participants were more likely to have a rural registered residence, a lower education level, no friends, be divorced or widowed, live alone, and lack knowledge of smartphones and reproductive health. The influence of COVID-19 had caused social activities to be more confined to the community, which impacts elderly HIV patients suffering from severe discrimination within families and communities.

Advances in experimental models of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by persistent articular inflammation and joint damage. RA was first described over 200 years ago; however, its etiology and pathophysiology remain insufficiently understood. The current treatment of RA is mainly empirical or based on the current understanding of etiology with limited efficacy and/or substantial side effects. Thus, the development of safer and more potent therapeutics, validated and optimized in experimental models, is urgently required. To improve the transition from bench to bedside, researchers must carefully select the appropriate experimental models as well as draw the right conclusions. Here, we summarize the establishment, pathological features, potential mechanisms, advantages, and limitations of the currently available RA models. The aim of the review is to help researchers better understand available RA models; discuss future trends in RA model development, which can help highlight new translational and human-based avenues in RA research.

Pullulanase with high temperature and low pH optima improved starch saccharification efficiency.

Pullulanase, a starch debranching enzyme, is required for the preparation of high glucose/maltose syrup from starch. In order to expand its narrow reaction conditions and improve its application value, Bacillus naganoensis pullulanase (PulA) was mutated by site-directed mutagenesis and the biochemical characteristics of the mutants were studied. The mutant PulA-N3 with mutations at asparagine 467, 492 and 709 residues was obtained. It displayed the activity maximum at 60 °C and pH 4.5 and exceeded 90% activities between 45 and 60 °C and from pH 4.0 to pH 5.5, which was improved greatly compared with wild-type PulA. Its thermostability and acidic pH stability were also remarkably improved. Its catalytic rate (kcat/Vmax) was 2.76 times that of PulA. In the preparation of high glucose syrup, the DX (glucose content, %) values of glucose mediated by PulA-N3 and glucoamylase reached 96.08%, which were 0.82% higher than that of PulA. In conclusion, a new pullulanase mutant PulA-N3 was successfully developed, which has high debranching activity in a wide range of temperature and pH, thereby paving the way for highly efficient starch saccharification.

Low CPEB1 levels may predict the benefit of 5-fluorouracil treatment in patients with colon or stomach adenocarcinoma.

Background: For patients with colon or stomach adenocarcinoma, 5-fluorouracil (5-FU) is an essential component of systemic chemotherapy in the palliative and adjuvant settings. The post-transcriptional regulatory factor cytoplasmic polyadenylation element-binding protein 1 (CPEB1) has been reported to be linked to tumor metastasis. This study aimed to investigate the relationship between CPEB1 expression and 5-FU treatment response in patients with colon and stomach adenocarcinomas. Methods: The expression of CPEB1 in stomach adenocarcinoma and colorectal cancer (CRC) tissues and in cell lines was determined by quantitative real-time PCR (qRT-PCR) and immunohistochemistry analyses. Transwell assays were employed to analyze the effects of CPEB1 on the migration and invasion abilities of gastric cancer (GC) and CRC cells. Results: The expression levels of CPEB1 were increased in colon and stomach adenocarcinoma and were negatively correlated with malignancy and poor patient survival. Data suggested that patients with CRC or GC who had strong CPEB1 expression responded poorly to 5-FU treatment. Furthermore, knockdown of CPEB1 inhibited the migration and invasion of CRC and GC cells via a mechanism involving decreased expression of matrix metalloprotein (MMP)2, 7, and 9. Finally, our methylated RNA immunoprecipitation PCR (meRIP qPCR) data suggested that the increased CPEB1 expression in colon and stomach adenocarcinomas might be mediated by FTO (FTO alpha-ketoglutarate dependent dioxygenase)-dependent m6A demethylation of CPEB1 mRNA. Conclusions: Our results indicate that the level of CPEB1 expression may be valuable for predicting the benefit of 5-FU treatment for patients with colon and stomach adenocarcinomas. We therefore propose that low CPEB1 expression may represent a novel biomarker for personalized 5-FU therapy.

High-efficiency chromosomal integrative amplification strategy for overexpressing α-amylase in Bacillus licheniformis.

Bacillus licheniformis is a well-known platform strain for production of industrial enzymes. However, the development of genetically stable recombinant B. licheniformis for high-yield enzyme production is still laborious. Here, a pair of plasmids, pUB-MazF and pUB'-EX1, were firstly constructed. pUB-MazF is a thermosensitive, self-replicable plasmid. It was able to efficiently cure from the host cell through induced expression of an endoribonuclease MazF, which is lethal to the host cell. pUB'-EX1 is a nonreplicative and integrative plasmid. Its replication was dependent on the thermosensitive replicase produced by pUB-MazF. Transformation of pUB'-EX1 into the B. licheniformis BL-UBM harboring pUB-MazF resulted in both plasmids coexisting in the host cell. At an elevated temperature, and in the presence of isopropyl-1-thio-ß-d-galactopyranoside and kanamycin, curing of the pUB-MazF and multiple-copy integration of pUB'-EX1 occurred, simultaneously. Through this procedure, genetically stable recombinants integrated multiple copies of amyS, from Geobacillus stearothermophilus ATCC 31195 were facilely obtained. The genetic stability of the recombinants was verified by repeated subculturing and shaking flask fermentations. The production of α-amylase by recombinant BLiS-002, harboring five copies of amyS, in a 50-l bioreactor reached 50 753 U/ml after 72 hr fermentation. This strategy therefore has potential for production of other enzymes in B. licheniformis and for genetic modification of other Bacillus species.

Decoupling analysis of carbon emissions in China's power industry-based on ARDL model.

Electric power industry, as one of the main industries leading to the increase of China's carbon emissions, accounts for about 40% of the total carbon emissions. It is of great practical significance to study the influencing factors of carbon emission decoupling index in power industry and put forward relevant policy suggestions. Based on the decoupling index of China's electric power industry from 1995 to 2018, this paper explores the influence of each index on the decoupling index through the autoregressive- distributed lag model. It turns out that the policy will significantly change the rate of change of carbon emissions and the rate of economic growth, but the impact of the policy is extremely short-lived; power generation structure, environmental regulations, and total lighting value at night play a positive role in promoting the decoupling index, while thermal power fuel efficiency and power generation conversion ratio play a negative role in inhibiting the decoupling index. In addition, the influence of power generation structure, environmental regulations, and the total value of night light on decoupling index also has a lagging and cumulative effect. Therefore, we propose targeted policy recommendations for policy formulation, green development, and low carbon construction in China's power industry from different perspectives based on the findings of the study.

Exploitation of ammonia-inducible promoters for enzyme overexpression in Bacillus licheniformis.

Ammonium hydroxide is conventionally used as an alkaline reagent and cost-effective nitrogen source in enzyme manufacturing processes. However, few ammonia-inducible enzyme expression systems have been described thus far. In this study, genomic-wide transcriptional changes in Bacillus licheniformis CBBD302 cultivated in media supplemented with ammonia were analyzed, resulting in identification of 1443 differently expressed genes, of which 859 genes were upregulated and 584 downregulated. Subsequently, the nucleotide sequences of ammonia-inducible promoters were analyzed and their functionally-mediated expression of amyL, encoding an α-amylase, was shown. TRNA_RS39005 (copA), TRNA_RS41250 (sacA), TRNA_RS23130 (pdpX), TRNA_RS42535 (ald), TRNA_RS31535 (plp), and TRNA_RS23240 (dfp) were selected out of the 859 upregulated genes and each showed higher transcription levels (FPKM values) in the presence of ammonia and glucose than that of the control. The promoters, PcopA from copA, PsacA from sacA, PpdpX from pdpX, Pald from ald, and Pplp from plp, except Pdfp from dfp, were able to mediate amyL expression and were significantly induced by ammonia. The highest enzyme expression level was mediated by Pplp and represented 23% more α-amylase activity after induction by ammonia in a 5-L fermenter. In conclusion, B. licheniformis possesses glucose-independent ammonia-inducible promoters, which can be used to mediate enzyme expression and therefore enhance the enzyme yield in fermentations conventionally fed with ammonia for pH adjustment and nitrogen supply.

Transmission Dynamics of the Rubella Virus Circulating in China During 2010-2019: 2 Lineage Switches Between Genotypes 1E and 2B.

BACKGROUND: To provide a better understanding of the progress on rubella control and elimination in China, a genetic analysis was conducted to examine the transmission pattern of the endemic rubella virus in China during 2010-2019. METHODS: A total of 4895 strains were obtained from 29 of the 31 provinces in mainland China during 2010-2019. The genotyping regions of the strains were amplified, determined, and assembled. Genotyping analysis and lineage division were performed by comparisons with the World Health Organization reference strains and reported lineage reference strains, respectively. Further phylogenetic analyses were performed to compare the genetic relationship. RESULTS: During 2010-2019, the domestic lineage 1E-L1 and multiple imported lineages of rubella viruses including 2B-L1, 1E-L2, and 2B-L2c were identified. Further analysis of the circulation trend of the different lineages indicated that 2 switches occurred among the lineages. The first shift was from lineage 1E-L1 to 2B-L1, which occurred around 2015-2016, followed by the lowest rubella incidence in 2017. The second shift was from lineage 2B-L1 to 1E-L2 and 2B-L2c, which occurred around 2018-2019, coinciding with rubella resurgence and the subsequent nationwide epidemic during 2018-2019. Insufficient genomic information worldwide made it impossible to trace the origin of the imported viruses. CONCLUSIONS: China was moving toward rubella elimination, as evidenced by the fact that previous endemic lineages were not detected. However, rubella reemerged in 2018 2019 due to the newly imported rubella viruses. Therefore, to realize the rubella elimination goal, joint efforts are required for all countries worldwide.

A novel aminopeptidase with potential debittering properties in casein and soybean protein hydrolysates.

A new aminopeptidase (An-APa) was identified and biochemically characterized from Aspergillus niger CICIM F0215. It had maximal activity at 40 °C and pH 7.0 and exhibited a broad substrate specificity both on hydrophilic and hydrophobic amino acid residues at N-terminals. With An-APa hydrolysis for 1 h, the casein-pepsin and soybean protein isolates (SPI)-pepsin hydrolysates released both hydrophilic and hydrophobic amino acids and the hydrophobic amino acids having Q values (degree of hydrophobicity) greater than 1500 cal/mol were remarkably released. Leu, Ile, Phe, Tyr, Trp, Pro, Val and Lys in the casein hydrolysate after treatment with An-APa increased 18.61, 0.84, 11.35, 13.18, 3.34, 6.30, 7.46, and 8.19 mg/100 mL, respectively, and 19.72, 1.47, 18.37, 11.72, 4.61, 4.10, 8.13, and 5.85 mg/100 mL, respectively, in the SPI hydrolysate. Both accounted for 65.0% and 64.4% of total released free amino acids from casein and SPI hydrolysates, respectively. This indicated that An-APa could be potentially applicable in debittering protein hydrolysates.

Biochemical characterization of two new Aspergillus niger aspartic proteases.

Two new aspartic proteases, PepAb and PepAc (encoded by pepAb and pepAc), were heterologously expressed and biochemically characterized from Aspergillus niger F0215. They possessed a typical structure of pepsin-type aspartic protease with the conserved active residues D (84, 115), Y (131, 168) and D (281, 326), while their identity in amino acid sequences was only 19.0%. PepAb had maximum activity at pH 2.5 and 50 °C and PepAc at 3.0 and 50 °C. The specific activities of PepAb and PepAc toward casein were 1368.1 and 2081.4 U/mg, respectively. Their activities were significantly promoted by Cu2+ and Mn2+ and completely inhibited by pepstatin. PepAb exhibited higher catalytic efficiency (k cat/K m) toward soy protein isolates than casein, while PepAc showed higher catalytic efficiency toward casein. The hydrolysis capacities of PepAb and PepAc on soy protein isolates were slightly lower than that of previously identified A. niger aspartic protease, PepA (aspergillopepsin I), while the resultant peptide profiles were remarkably different for all three proteases.

Twin-arginine signal peptide of Bacillus licheniformis GlmU efficiently mediated secretory expression of protein glutaminase

Background: Protein glutaminase specifically deamidates glutamine residue in protein and therefore significantly improves protein solubility and colloidal stability of protein solution. In order to improve its preparation efficiency, we exploited the possibility for its secretory expression mediated by twin-arginine translocation (Tat) pathway in Bacillus licheniformis. Results: The B. licheniformis genome-wide twin-arginine signal peptides were analyzed. Of which, eleven candidates were cloned for construction of expression vectors to mediate the expression of Chryseobacterium proteolyticum protein glutaminase (PGA). The signal peptide of GlmU was confirmed that it significantly mediated PGA secretion into media with the maximum activity of 0.16 U/ml in Bacillus subtilis WB600. A mutant GlmU-R, being replaced the third residue aspartic acid of GlmU twin-arginine signal peptide with arginine by site-directed mutagenesis, mediated the improved secretion of PGA with about 40% increased (0.23 U/ml). In B. licheniformis CBBD302, GlmU-R mediated PGA expression in active form with the maximum yield of 6.8 U/ml in a 25-l bioreactor. Conclusions: PGA can be produced and secreted efficiently in active form via Tat pathway of B. licheniformis, an alternative expression system for the industrial-scale production of PGA.

Predictive value of combining the level of lipoprotein-associated phospholipase A2 and antithrombin III for acute coronary syndrome risk.

The aim of the present study was to observe the role of lipoprotein-associated phospholipase A2 (Lp-PLA2) and antithrombin III (AT-III) in patients with acute coronary syndrome (ACS), and the combination of Global Registry of Acute Coronary Events (GRACE) score to determine the value of coronary heart disease risk stratification. A total of 309 patients admitted to the Affiliated Hospital of Xuzhou Medical University were enrolled. The patients were divided into two groups: The ACS (183 cases) and control (126 cases) groups. Blood levels of Lp-PLA2 and AT-III were measured. Based on GRACE score, the patients with ACS were divided into three subgroups: Low risk (GRACE score ≤108), middle risk (GRACE score 109-140) and high risk (GRACE score >140). The levels of Lp-PLA2 and AT-III were compared among different groups, and based on Gensini score, patients with ACS were divided into four groups by quartiles. Lp-PLA2 levels in the ACS group were significantly increased compared with the control group (P<0.05), but the AT-III levels were decreased compared with the control group (P<0.05). In the ACS group, Lp-PLA2 levels increased sequentially from the low risk to high risk subgroups (all P<0.05); compared with the low risk and middle risk subgroups, the AT-III activity levels were decreased in the high risk subgroup, and the Gensini scores were increased (all P<0.05). In the ACS group, with the increase of Gensini scores, the levels of Lp-PLA2 and AT-III exhibited increasing and decreasing trends, respectively (P<0.05). The logistic regression model demonstrated that Lp-PLA2 [odds ratio (OR) =1.077; P<0.001]; and GRACE score (OR=1.026; P=0.028) were risk factors, while AT-III was a protective factor (OR=0.958; P=0.012) for ACS. Correlation analysis indicated a positive association of Lp-PLA2 level with Gensini scores (r=0.52; P<0.01) and GRACE score (r=0.48; P<0.01), and a negative association between AT-III level and Gensini scores (r=-0.25; P<0.01) and GRACE scores (r=-0.34; P<0.01). The levels of Lp-PLA2 and AT-III exhibited predictive values in patients with ACS, and are associated with the severity of coronary artery stenosis.

Effects of hydration combined with Shenfu injection on contrast-induced acute kidney injury in acute coronary syndrome patients undergoing percutaneous coronary intervention.

The aim of the present study was to evaluate the efficacy and safety of the Shenfu injection (SFI) in the prevention of contrast-induced acute kidney injury (CI-AKI) in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). A single-center prospective and randomized controlled trial was performed and 148 ACS patients undergoing PCI were divided randomly into control (n=74; receiving only 0.9% sodium chloride solution for routine hydration) and intervention (n=74; based upon routine hydration and receiving SFI) groups. Serum creatinine (Scr), blood urea nitrogen and urinary neutrophil gelatinase-associated lipocalin (NGAL) were evaluated at the start, and 1 and 2 days after PCI. Among the 148 patients, 14 (9.4%) experienced CI-AKI subsequent to the procedure. CI-AKI occurred in 2.7% of the SFI group and 16.2% of the control group (P<0.05). The incidence of CI-AKI was lower in the intervention group when compared with the control. No serious adverse effects were observed in all patients. No differences between the levels of Scr and estimated glomerular filtration rate in the two groups were identified. However, 12 h after PCI, the urinary NGAL level in the control group was significantly higher than that in the SFI group (P<0.05). Thus, hydration combined with SFI was identified to be more effective than hydration with sodium chloride in the prevention of CI-AKI in ACS patients undergoing PCI.

Biochemical characterization of three Aspergillus niger ß-galactosidases

Background: ß-Galactosidases catalyze both hydrolytic and transgalactosylation reactions and therefore have many applications in food, medical, and biotechnological fields. Aspergillus niger has been a main source of ß-galactosidase, but the properties of this enzyme are incompletely studied. Results: Three new ß-galactosidases belonging to glycosyl hydrolase family 35 from A. niger F0215 were cloned, expressed, and biochemically characterized. In addition to the known activity of LacA encoded by lacA, three putative ß-galactosidases, designated as LacB, LacC, and LacE encoded by the genes lacB, lacC, and lacE, respectively, were successfully cloned, sequenced, and expressed and secreted by Pichia pastoris. These three proteins and LacA have N-terminal signal sequences and are therefore predicted to be extracellular enzymes. They have the typical structure of fungal ß-galactosidases with defined hydrolytic and transgalactosylation activities on lactose. However, their activity properties differed. In particular, LacB and lacE displayed maximum hydrolytic activity at pH 4­5 and 50°C, while LacC exhibited maximum activity at pH 3.5 and 60°C. All ß-galactosidases performed transgalactosylation activity optimally in an acidic environment. Conclusions: Three new ß-galactosidases belonging to glycosyl hydrolase family 35 from A. niger F0215 were cloned and biochemically characterized. In addition to the known LacA, A. niger has at least three ß-galactosidase family members with remarkably different biochemical properties.