Production and pharmaceutical research of minor saponins in Panax notoginseng (Sanqi): Current status and future prospects

Panax notoginseng (Burk.) F.H. Chen is a traditional medicinal herb known as Sanqi or Tianqi in Asia and is commonly used worldwide. It is one of the main raw ingredients of Yunnan Baiyao, Fu fang dan shen di wan, and San qi shang yao pian. It is also a source of cardiotonic pill used to treat cardiovascular diseases in China, Korea, and Russia. Approximately 270 Panax notoginseng saponins have been isolated and identified as the major active components. Although the absorption and bioavailability of saponins are predominantly dependent on the gastrointestinal biotransformation capacity of an individual, minor saponins are better absorbed into the bloodstream and act as active substances than major saponins. Notably, minor saponins are absent or are present in minimal quantities under natural conditions. In this review, we focus on the strategies for the enrichment and production of minor saponins in P. notoginseng using physical, chemical, enzyme catalytic, and microbial methods. Moreover, pharmacological studies on minor saponins derived from P. notoginseng over the last decade are discussed. This review serves as a meaningful resource and guide, offering scholarly references for delving deeper into the exploration of the minor saponins in P. notoginseng.

Biotransformation approach to produce rare ginsenosides F1, compound Mc1, and Rd2 from major ginsenosides

The stems and leaves of Panax notoginseng contain high saponins, but they are often discarded as agricultural waste. In this study, the predominant ginsenosides Rg1, Rc, and Rb2, presented in the stems and leaves of ginseng plants, were biotransformed into value-added rare ginsenosides F1, compound Mc1 (C-Mc1), and Rd2, respectively. A fungal strain YMS6 (Penicillium sp.) was screened from the soil as a biocatalyst with high selectivity for the deglycosylation of major ginsenosides. Under the optimal fermentation conditions, the yields of F1, C-Mc1, and Rd2 were 97.95, 68.64, and 79.58%, respectively. This study provides a new microbial resource for the selective conversion of protopanaxadiol-type and protopanaxatriol-type major saponins into rare ginsenosides via the whole-cell biotransformation and offers a solution for the better utilization of P. notoginseng waste.

Biotransformation of Sclareol by a Fungal Endophyte of Salvia sclarea

Microbial endophytes are known as versatile producers of useful metabolites, which have extensive applications in pharmacy, fragrance, agriculture and food. This study aims to screen sclareol-biotransforming microorganisms from Salvia sclarea, an untapped source of diverse endophytes. In this study, 50 culturable endophytes were isolated from S. sclarea grown in Xinjiang using sclareol as the sole carbon source and screened for their potential to transform sclareol into analogues. A fungal endophyte, identified as the generally recognized as safe (GRAS) strain Aspergillus tubingensis, can produce labd-14-ene-3β,8α,13β-triol and 8α,13β-dihydroxylabd-14-en-3-one from sclareol, involving hydroxylation and carbonylation at the C3 site. Structures of the two metabolites were elucidated by HR-ESI-MS and NMR analysis. S. sclarea was proven to be a good source of endophytes that are prospective producers of secondary metabolites with valuable chemical and biological properties. This study is the first report regarding the isolation of endophytes from S. sclarea.

A randomized trial of eribulin monotherapy versus eribulin plus anlotinib in patients with locally recurrent or metastatic breast cancer

BACKGROUND

Eribulin mesylate is a novel, nontaxane, microtubule dynamics inhibitor. In this study, we assessed the efficacy and safety of eribulin versus eribulin plus the oral small-molecule tyrosine kinase inhibitor anlotinib in patients with locally recurrent or metastatic breast cancer.

PATIENTS AND METHODS

In this single-center, open-label, phase II clinical study (NCT05206656) conducted in a Chinese hospital, patients with human epidermal growth factor receptor 2 (HER2)-negative, locally recurrent or metastatic breast cancer previously treated with anthracycline- or taxane-based chemotherapy were randomized (1 : 1) to receive eribulin alone or in combination with anlotinib. The primary efficacy endpoint was investigator-assessed progression-free survival (PFS).

RESULTS

From June 2020 to April 2022, a total of 80 patients were randomly assigned to either eribulin monotherapy or eribulin plus anlotinib combination therapy, with 40 patients in each group. The data cut-off was 10 August 2022. The median PFS was 3.5 months [95% confidence interval (CI) 2.8-5.5 months] for eribulin and 5.1 months (95% CI 4.5-6.9 months) for eribulin plus anlotinib (hazard ratio = 0.56, 95% CI 0.32-0.98; P = 0.04). The objective response rates were 32.5% versus 52.5% (P = 0.07), respectively, and disease control rates were 67.5% versus 92.5% (P = 0.01), respectively. Patients <50 years of age, with an Eastern Cooperative Oncology Group performance status score of 0, visceral metastasis, number of treatment lines of four or more, hormone receptor negative (triple-negative), and HER2 low expression appeared to benefit more from combined treatment. The most common adverse events in both groups were leukopenia (n = 28, 70.0%, patients in the eribulin monotherapy group versus n = 35, 87.5%, patients in the combination therapy group), aspartate aminotransferase elevations (n = 28, 70.0%, versus n = 35, 87.5%), neutropenia (n = 25, 62.5%, versus n = 31, 77.5%), and alanine aminotransferase elevations (n = 25, 62.5%, versus n = 30, 75.0%).

CONCLUSION

Eribulin plus anlotinib can be considered an alternative treatment option for HER2-negative locally advanced or metastatic breast cancer.

SLC7A11-associated ferroptosis in acute injury diseases: mechanisms and strategies

Ferroptosis is a kind of iron-dependent renewal programmed death. Its main mechanism is to catalyze the unsaturated fatty acids highly expressed on the cell membrane under the effect of divalent iron, to produce lipid peroxidation, thus inducing cell death. SLC7A11 is a known iron death-related factor. It has been proved that iron death is involved in the occurrence and development of acute diseases, but the specific mechanism is unknown. The purpose of this review is to highlight the regulatory properties of SLC7A11 and gain a deeper understanding of its role in ferroptosis-related acute injury diseases. This is a narrative review. PubMed was used as the main source to randomly implement literature search strategy to index Scopus articles. No specific terms are used. Studies have shown that SLC7A11 may affect the sensitivity of cells to iron ptosis by regulating it at the transcriptional or post-transcriptional level, which is related to the pathology of many acute injury diseases, such as acute lung injury (ALI), acute kidney injury (AKI), acute liver injury, myocardial ischemia-reperfusion injury, and acute cerebral hemorrhage. In order to clarify this point, more and more researchers turn their attention to the study of the specific mechanism between SLC7A11 and ferroptosis-related acute injury diseases. In summary, this review summarized some specific mechanisms by which ferroptosis could be controlled by SLC7A11 and clarified the underlying mechanisms of a series of diseases caused by SLC7A11-associated ferroptosis. It also provided more scientific justification for the clinical application of targeting ferroptosis in preventing and treating various diseases.

Efficient biosynthesis of resveratrol via combining phenylalanine and tyrosine pathways in Saccharomyces cerevisiae

BACKGROUND

Resveratrol is a commercially available stilbenoid widely used as dietary supplements, functional food ingredients, and cosmetic ingredients due to its diverse physiological activities. The production of resveratrol in microorganisms provides an ideal source that reduces the cost of resveratrol, but the titer in Saccharomyces cerevisiae was still much lower than that in other hosts.

RESULTS

To achieve enhanced production of resveratrol in S. cerevisiae, we constructed a biosynthetic pathway via combining phenylalanine and tyrosine pathways by introducing a bi-functional phenylalanine/tyrosine ammonia lyase from Rhodotorula toruloides. The combination of phenylalanine pathway with tyrosine pathway led to a 462% improvement of resveratrol production in yeast extract peptone dextrose (YPD) medium with 4% glucose, suggesting an alternative strategy for producing p-coumaric acid-derived compounds. Then the strains were further modified by integrating multi-copy biosynthetic pathway genes, improving metabolic flux to aromatic amino acids and malonyl-CoA, and deleting by-pathway genes, which resulted in 1155.0 mg/L resveratrol in shake flasks when cultured in YPD medium. Finally, a non-auxotrophic strain was tailored for resveratrol production in minimal medium without exogenous amino acid addition, and the highest resveratrol titer (4.1 g/L) ever reported was achieved in S. cerevisiae to our knowledge.

CONCLUSIONS

This study demonstrates the advantage of employing a bi-functional phenylalanine/tyrosine ammonia lyase in the biosynthetic pathway of resveratrol, suggesting an effective alternative in the production of p-coumaric acid-derived compounds. Moreover, the enhanced production of resveratrol in S. cerevisiae lays a foundation for constructing cell factories for various stilbenoids.

Metabolic Engineering of Escherichia coli for High-Level Production of (R)-Acetoin from Low-Cost Raw Materials

Acetoin is an important four-carbon platform chemical with versatile applications. Optically pure (R)-acetoin is more valuable than the racemate as it can be applied in the asymmetric synthesis of optically active α-hydroxy ketone derivatives, pharmaceuticals, and liquid crystal composites. As a cytotoxic solvent, acetoin at high concentrations severely limits culture performance and impedes the acetoin yield of cell factories. In this study, putative genes that may improve the resistance to acetoin for Escherichia coli were screened. To obtain a high-producing strain, the identified acetoin-resistance gene was overexpressed, and the synthetic pathway of (R)-acetoin was strengthened by optimizing the copy number of the key genes. The engineered E. coli strain GXASR-49RSF produced 81.62 g/L (R)-acetoin with an enantiomeric purity of 96.5% in the fed-batch fermentation using non-food raw materials in a 3-L fermenter. Combining the systematic approach developed in this study with the use of low-cost feedstock showed great potential for (R)-acetoin production via this cost-effective biotechnological process.

High-yield production of protopanaxadiol from sugarcane molasses by metabolically engineered Saccharomyces cerevisiae

Background

Ginsenosides are Panax plant-derived triterpenoid with wide applications in cardiovascular protection and immunity-boosting. However, the saponins content of Panax plants is fairly low, making it time-consuming and unsustainable by direct extraction. Protopanaxadiol (PPD) is a common precursor of dammarane-type saponins, and its sufficient supply is necessary for the efficient synthesis of ginsenoside.

Results

In this study, a combinational strategy was used for the construction of an efficient yeast cell factory for PPD production. Firstly, a PPD-producing strain was successfully constructed by modular engineering in Saccharomyces cerevisiae BY4742 at the multi-copy sites. Then, the INO2 gene, encoding a transcriptional activator of the phospholipid biosynthesis, was fine-tuned to promote the endoplasmic reticulum (ER) proliferation and improve the catalytic efficiency of ER-localized enzymes. To increase the metabolic flux of PPD, dynamic control, based on a carbon-source regulated promoter P_HXT1, was introduced to repress the competition of sterols. Furthermore, the global transcription factor UPC2-1 was introduced to sterol homeostasis and up-regulate the MVA pathway, and the resulting strain BY-V achieved a PPD production of 78.13 ± 0.38 mg/g DCW (563.60 ± 1.65 mg/L). Finally, sugarcane molasses was used as an inexpensive substrate for the first time in PPD synthesis. The PPD titers reached 1.55 ± 0.02 and 15.88 ± 0.65 g/L in shake flasks and a 5-L bioreactor, respectively. To the best of our knowledge, these results were new records on PPD production.

Conclusion

The high-level of PPD production in this study and the successful comprehensive utilization of low-cost carbon source -sugarcane molassesindicate that the constructed yeast cell factory is an excellent candidate strain for the production of high-value-added PPD and its derivativeswith great industrial potential.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-022-01949-4.

Probing the Biotransformation Process of Sclareol by Resting Cells of Hyphozyma roseonigra

Sclareol glycol is a key starting material with significant market interest for synthesizing high-value ambroxide, a sustainable substitute for ambergris in high-end fragrances. Sclareol glycol can be obtained by biotransformation of sclareol, a labdane-type diterpene, using Hyphozyma roseonigra. However, the pathway and mechanism of sclareol glycol biosynthesis remain unclear. In this study, the dynamic time course of sclareol biotransformation was explored by resting cell assays and several intermediates produced during biotransformation were detected. The results show that (1) sclareol glycol and sclareolide are not interconverted and are potentially synthesized via different metabolic pathways and (2) several putative intermediates resulting from biotransformation are featured with a labdane carbon backbone, including isomerized and oxidized analogues. A plausible transformation pathway of sclareol in H. roseonigra was proposed based on detected metabolites. This study sheds light on the biosynthetic mechanism of sclareol glycol and paves a way for the future biotechnological production of this promising compound.

[HIV infection status and related factors in men who have sex with men in sentinel surveillance in Shanxi province, 2010, 2015 and 2020]

Objective: To understand the infection status of HIV and related factors in men who have sex with men (MSM) in Shanxi province in 2010, 2015 and 2020. Methods: According to the sentinel surveillance protocol, continuous cross-sectional survey were conducted to collect the information about basic characteristics, general demographic characteristics, AIDS knowledge awareness, high-risk sexual behavior, sexually transmitted diseases, intervention services and HIV infection rate of the MSM in Shanxi in 2010, 2015 and 2020. Results: In 2010, 2015 and 2020, a total of 2 708 MSM were included in this study. There were significant differences in HIV infection rate among three years (χ²=23.76, P<0.001) with an increasing trend with year (trend χ² =17.34, P<0.001). The rates of anal sex, commercial sex and heterosexual behavior in the past 6 months were 77.62% (2 102/2 708), 5.91% (160/2 708) and 28.14% (762/2 708) respectively, and the rates of consistent use of condom were 52.52% (1 104/2 102), 63.13% (101/160) and 23.49%(179/762) respectively, and the rate of consistent condom use was low. Results from multivariate logistic regression analysis showed that different cities, having educational level of junior high school or below, being recruited through internet, voluntary counseling and testing, suffering from sexually transmitted diseases, occasional condom use in anal sex in the past 6 months were the correlative factors of HIV infection of MSM. Conclusions: The HIV infection rate of MSM in Shanxi increased year by year from 2010, 2015 to 2020. The HIV/AIDS-related risk behavior persisted, and the proportion of condomuse adherence was low, and the HIV detection rate was low in the MSM, so targeted and effective measures should be taken to promote the condom use adherence and regular HIV testing in MSM.

De Novo Biosynthesis of D-p-Hydroxyphenylglycine by a Designed Cofactor Self-Sufficient Route and Co-culture Strategy

d-p-Hydroxyphenylglycine (D-HPG) is an important intermediate for the synthesis of β-lactam antibiotics with an annual market demand of thousands of tons. Currently, the main production processes are via chemical approaches. Although enzymatic conversion has been investigated for D-HPG production, synthesis of the substrate DL-hydroxyphenylhydantoin is still chemically based, which suffers from high pollution and harsh reaction conditions. In this study, one cofactor self-sufficient route for D-HPG production from l-phenylalanine was newly designed and the artificial pathway was functionalized by selecting suitable enzymes and adjusting their expressions in strain Pseudomonas putida KT2440. Notably, a new R-mandelate dehydrogenase from Lactococcus lactis with relatively high activity under pH neutral conditions was successfully mined to demonstrate the biosynthetic pathway in vivo. The performance of the engineered P. putida strain was further increased by enhancing cellular NAD availability and blocking l-phenylalanine consumption. Coupled with the l-phenylalanine producer, Escherichia coli strain ATCC 31884, a stable and interactive co-culture process was also developed by engineering a "cross-link auxotrophic" system to produce D-HPG directly from glucose. Thus, this study is the first approach for the de novo biosynthesis of D-HPG by engineering a non-natural pathway and lays the foundation for further improving the efficiency of D-HPG production via a green and sustainable route.

The value of MRCP in children with biliary symptomatology - an essential adjunct for safe cholecystectomy

Congenital abnormalities of the biliary system are a consideration in children with biliary symptomatology. The preoperative diagnosis rate is still not satisfactory, despite progresses made in imaging technology, with the potential of biliary tract injury if surgery is indicated. The double gallbladder is a rare developmental abnormality of the biliary tract with several anatomical variations. This abnormality was accurately delineated in a 7-year-old child by MRI/MRCP, allowing the ductal anatomy to be accurately identified and safe laparoscopic cholecystectomies to be performed.

Characterization of a Group of UDP-Glycosyltransferases Involved in the Biosynthesis of Triterpenoid Saponins of Panax notoginseng

UDP-glycosyltransferase (UGT)-mediated glycosylation is a common modification in triterpene saponins, which exhibit a wide range of bioactivities and important pharmacological effects. However, few UGTs involved in saponin biosynthesis have been identified, limiting the biosynthesis of saponins. In this study, an efficient heterologous expression system was established for evaluating the UGT-mediated glycosylation process of triterpene saponins. Six UGTs (UGTPn17, UGTPn42, UGTPn35, UGTPn87, UGTPn19, and UGTPn12) from Panax notoginseng were predicted and found to be responsible for efficient and direct enzymatic biotransformation of 21 triterpenoid saponins via 26 various glycosylation reactions. Among them, UGTPn87 exhibited promiscuous sugar-donor specificity of UDP-glucose (UDP-Glc) and UDP-xylose (UDP-Xyl) by catalyzing the elongation of the second sugar chain at the C3 or/and C20 sites of protopanaxadiol-type saponins with a UDP-Glc or UDP-Xyl donor, as well as at the C20 site of protopanaxadiol-type saponins with a UDP-Glc donor. Two new saponins, Fd-Xyl and Fe-Xyl, were generated by catalyzing the C3-O-Glc xylosylations of notoginsenoside Fd and notoginsenoside Fe when incubated with UGTPn87. Moreover, the complete biosynthetic pathways of 17 saponins were elucidated, among which notoginsenoside L, vinaginsenoside R16, gypenoside LXXV, and gypenoside XVII were revealed in Panax for the first time. A yeast cell factory was constructed with a yield of Rh2 at 354.69 mg/L and a glycosylation ratio of 60.40% in flasks. Our results reveal the biosynthetic pathway of a group of saponins in P. notoginseng and provide a theoretical basis for producing rare and valuable saponins, promoting their industrial application in medicine and functional foods.

A Green Route for High-Yield Production of Tetramethylpyrazine From Non-Food Raw Materials

2,3,5,6-Tetramethylpyrazine (TMP) is an active pharmaceutical ingredient originally isolated from Ligusticum wallichii for curing cardiovascular and cerebrovascular diseases and is widely used as a popular flavoring additive in the food industry. Hence, there is a great interest in developing new strategies to produce this high-value compound in an ecological and economical way. Herein, a cost-competitive combinational approach was proposed to accomplish green and high-efficiency production of TMP. First, microbial cell factories were constructed to produce acetoin (3-hydroxy-2-butanone, AC), an endogenous precursor of TMP, by introducing a biosynthesis pathway coupled with an intracellular NAD⁺ regeneration system to the wild-type Escherichia coli. To further improve the production of (R)-AC, the metabolic pathways of by-products were impaired or blocked stepwise by gene manipulation, resulting in 40.84 g/L (R)-AC with a high optical purity of 99.42% in shake flasks. Thereafter, an optimal strain designated GXASR11 was used to convert the hydrolysates of inexpensive feedstocks into (R)-AC and achieved a titer of 86.04 g/L within 48 h in a 5-L fermenter under optimized fermentation conditions. To the best of our knowledge, this is the highest (R)-AC production with high optical purity (≥98%) produced from non-food raw materials using recombinant E. coli. The supernatant of fermentation broth was mixed with diammonium phosphate (DAP) to make a total volume of 20 ml and transferred to a high-pressure microreactor. Finally, 56.72 g/L TMP was obtained in 3 h via the condensation reaction with a high conversion rate (85.30%) under optimal reaction conditions. These results demonstrated a green and sustainable approach to efficiently produce high-valued TMP, which realized value addition of low-cost renewables.

Malnutrition Increases the Risk of Left Ventricular Remodeling

OBJECTIVES

Malnutrition is associated with increased incidence of heart failure (HF). Left ventricular (LV) remodeling is one of the most important processes in the occurrence and evolution of HF. However, the association between nutritional status and LV remodeling is not well known. The study aimed to investigate the association between malnutrition and LV remodeling.

DESIGN

The study was a retrospective observation study.

SETTING AND PARTICIPANTS

We included patients from the registry of Cardiorenal Improvement study from January 2007 to December 2018 at Guangdong Provincial People's Hospital.

MEASUREMENTS

The primary endpoint was LV remodeling, defined as an absolute decrease in LV ejection fraction ≥10% after discharge compared with baseline. Nutritional status was assessed by the Controlling Nutritional Status (CONUT) score. Eligible patients were divided into absent-mild malnutrition group (CONUT score ≤4) and moderate-severe malnutrition group (CONUT score >4). Univariable and multivariable logistic regression was performed to verify the association between malnutrition and left ventricular remodeling.

RESULTS

A total of 7,217 patients (mean age 61.3±10.5 years, 71.7% male) were included in the final analysis, among which 712 (9.9%) had LV remodeling. The incidence of LV remodeling in moderate-severe malnutrition group was significantly higher than that in absent-mild malnutrition group (12.9% vs. 9.5%, p=0.002). In multivariable logistic regression, moderate-severe malnutrition group was significantly associated with 1.69-fold increased risk of LV remodeling after adjusting confounders (OR: 1.69, CI: 1.32-2.16). Similar results were observed in subgroup stratified by age, gender, and coronary artery disease.

CONCLUSION

Nearly one eighth of patients were classified as moderate-severe malnutrition, 12% of whom had LV remodeling. Moderate-severe malnutrition was associated with 69% increased risk of LV remodeling. Further studies are needed to prospectively evaluate the nutrition-oriented managements on outcomes in LV remodeling.

The Efficacy of Pyrotinib as a Third- or Higher-Line Treatment in HER2-Positive Metastatic Breast Cancer Patients Exposed to Lapatinib Compared to Lapatinib-Naive Patients: A Real-World Study

Background: Pyrotinib is a novel irreversible pan-ErbB receptor tyrosine kinase inhibitor. Evidence of the efficacy of pyrotinib-based treatments for HER2-positive metastatic breast cancer (MBC) in patients exposed to lapatinib is limited.

Methods: Ninety-four patients who received pyrotinib as a third- or higher-line treatment for HER2-positive MBC were included in this retrospective study. The primary and secondary endpoints were overall survival (OS) and progression‐free survival (PFS). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were implemented to balance important patient characteristics between groups.

Results: Thirty (31.9%) patients were pretreated with lapatinib and subsequently received pyrotinib as an anti-HER2 treatment, and 64 (68.1%) patients did not receive this treatment. The OS and PFS indicated a beneficial trend in lapatinib-naive group compared to lapatinib-treated group in either the original cohort (PFS: 9.02 vs 6.36 months, p = 0.05; OS: 20.73 vs 14.35 months, p = 0.08) or the PSM (PFS: 9.02 vs 6.08 months, p = 0.07; OS: 19.07 vs 18.00 months, p = 0.61) or IPTW (PFS: 9.90 vs 6.17 months, p = 0.05; OS: 19.53 vs 15.10 months, p = 0.08) cohorts. Subgroup analyses demonstrated lapatinib treatment-related differences in PFS in the premenopausal subgroup and the no prior trastuzumab treatment subgroup, but no significant differences were observed in OS.

Conclusion: Pyrotinib-based therapy demonstrated promising effects in HER2-positive MBC patients in a real-world study, especially in lapatinib-naive patients, and also some activity in lapatinib-treated patients.

[Epidemiological and Etiologic characteristics of Meningococcal meningitis in Xinjiang Uygur Autonomous Region,1960-2019]

Objective: To understand the epidemiological and etiologic characteristics of meningococcal meningitis in Xinjiang Uygur Autonomous Region (Xinjiang). Methods: The epidemiological data about the meningococcal meningitis cases in Xinjiang from 1960 to 2019 were collected from the China information system for disease control and prevention and the Center for Disease Control and Prevention of Xinjiang. The epidemiological characteristics were analyzed. Clinical specimens from suspected cases were cultured and tested by real-time PCR method. A survey on the carriage rate of Neisseria meningitides (Nm) in the healthy population was performed. The serogroups of isolates were determined by serum-agglutination and PCR methods. Multi-locus sequence typing was used for subtyping the isolates. Results: The incidence rates of meningococcal meningitis in Xinjiang from 1960 to 2019 were 0.02/100 000-81.32/100 000, with the mortality as 1.05%-20.78%. The five districts with the most cases were Kashi prefecture, Aksu prefecture, Urumqi city, Changji Hui autonomous prefecture, and Hotan prefecture. Before 1990, serogroup A (81.82%) was the commonest group for cases and contacts. After 1990, 14.00% of the cases were caused by serogroups B, C, W, and Y. There was no predominant serogroup for contacts with serogroups B, C, W, Y, and C accounting for 23.28%, 18.53%, 15.52%, 9.91% and 7.33% respectively. The general Nm carriage rate was 15.50%, with the population of 16 - 20 years age group having the highest rate (25.53%). Serogroups B (52.11%), W (20.66%), C (12.21%), and Y (9.39%) occupied 52.11%, 20.66%, 12.21% and 9.39% respectively. The commonest clonal lineages of Nm isolates were ST-4821, ST-175, and ST-5 clonal complexes, while the ST-5 and ST-4821 clonal complexes were the major ones for invasive strains. Conclusions: There appeared regional differences in the incidence rates of Xinjiang meningococcal meningitis, and the carriage rate of Nm was high. The serogroups have been changing. It is necessary to strengthen the prevention and control of meningococcal meningitis to prevent any potential outbreak.

De Novo Biosynthesis of Polydatin in Saccharomyces cerevisiae

Polydatin, with better structural stability and biological activities than resveratrol, is mainly extracted from the traditional Chinese medicinal plant Polygonum cuspidatum. In this study, based on the transcriptome analysis of P. cuspidatum, we identified the key glycosyltransferase of resveratrol and achieved the biosynthesis of polydatin from glucose by incorporation with the resveratrol biosynthesis module, UDP-glucose supply module, and glycosyltransferase expression module. Through metabolic engineering and fermentation optimization, the production of polydatin reached 545 mg/L, and the dry cell weight was 27.83 mg/g DCW, which was about twice that of extracted from the P. cuspidatum root (11.404 mg/g DCW). Therefore, it is possible to replace the production mode of polydatin from plant extraction to microbial chassis in the future.

Bone marrow mesenchymal stem cells-induced exosomal microRNA-486-3p protects against diabetic retinopathy through TLR4/NF-κB axis repression

AIM

Diabetic retinopathy (DR) is a chronic disease causing health and economic burdens on individuals and society. Thus, this study is conducted to figure out the mechanisms of bone marrow mesenchymal stem cells (BMSCs)-induced exosomal microRNA-486-3p (miR-486-3p) in DR.

METHODS

The putative miR-486-3p binding sites to 3'untranslated region of Toll-like receptor 4 (TLR4) was verified by luciferase reporter assay. High glucose (HG)-treated Muller cells were transfected with miR-486-3p or TLR4-related oligonucleotides and plasmids to explore theirs functions in DR. Additionally, HG-treated Muller cells were co-cultured with BMSC-derived exosomes, exosomes collected from BMSCs that had been transfected with miR-486-3p or TLR4-related oligonucleotides and plasmids to explore their functions in DR. MiR-486-3p, TLR4 and nuclear factor-kappaB (NF-κB) expression, angiogenesis-related factors, oxidative stress factors, viability and apoptosis in HG-treated Muller cells were detected by RT-qPCR, western blot analysis, ELISA, MTT assay and flow cytometry, respectively.

RESULTS

MiR-486-3p was poorly expressed while TLR4 and NF-κB were highly expressed in HG-treated Muller cells. TLR4 was a target of miR-486-3p. Upregulating miR-486-3p or down-regulating TLR4 inhibited oxidative stress, inflammation and apoptosis, and promoted proliferation of HG-treated Muller cells. Meanwhile, BMSC-derived exosomes inhibited oxidative stress, inflammation and apoptosis, and promoted proliferation of HG-treated Muller cells. Restoring miR-486-3p further enhanced, while up-regulating TLR4 reversed, the improvement of exosomes treatment.

CONCLUSION

Our study highlights that up-regulation of miR-486-3p induced by BMSC-derived exosomes played a protective role in DR mice via TLR4/NF-κB axis repression.

[In vitro study of non-thermal atmospheric plasma influencing the surface properties of dentin]

Objective: To study the influence of non-thermal atmospheric pressure plasma (NTAPP) on dentine surface temperature, wettability and morphology of collagen fibrils under different treatment condition. Methods: Helium was used as the operating gas at the flow rate of 3, 4, 5 L/min respectively. The plasma jet was operated at various input power of 8, 9, 10, 11 W. Thermal accumulation on human dentine surface (6 specimens per group, acquired from Department of Stomatology, The First Affiliated Hospital of Xi'an Medical University and Department of Stomatology, The Second Affiliated Hospital of Xi'an Medical University) of each group was measured continuously at 5 s intervals for 60 s by infrared thermography. Mean values were calculated and temperature curves were drawn. Dentine surface contact angles were measured after NTAPP treatment for 5, 10, 15, 20 s with gas flow rate and input power described above. The micro structure of the collagen fibrils of the negative control group (without NTAPP treatment) and NTAPP treatment groups (5 L/min gas flow rate, input power of 8, 9, 10, 11 W and treating time for 5, 10, 15, 20 s) was observed by field emission scanning electron microscopy (FE-SEM). All data were analyzed by SPSS 18.0. Results: Input power, gas flow and treatment time all showed significant influences on dentine surface temperature and wettability (P<0.01). Dentine temperature rose along with time. The greater input power was, the higher dentine temperature was. The greater gas flow rate was, the faster the temperature rose. Dentine surface temperature reached the highest point of (35.10±0.24) ℃ with NTAPP treatment for 60 s, at input power of 11 W and flow rate of 5 L/min. The contact angles of each experimental group decreased with time, and significant differences were found in the contact angles between the experimental groups and the negative control group (75.57°±1.45°). The contact angles showed a decreasing trend as the input power and the gas flow rate increased. The contact angles reached the lowest point of 13.19°±2.01° with NTAPP treatment for 20 s, at input power of 10 W and flow rate of 5 L/min. The FE-SEM results showed that, along with the increase of input power and extension of time, the demineralized collagen fibrils were destroyed in varying degrees. The collagen fibrils were curled, fractured, fused, and even disappeared. Conclusions: NTAPP could significantly increase the surface temperature, modify dentine wettability and alter the micro structure, which was significantly influenced by input power, gas flow rate and treating time.

Improved light extraction efficiency of AlGaN deep-ultraviolet light emitting diodes combining Ag-nanodots/Al reflective electrode with highly transparent p-type layer

Enhancement of light extraction efficiency (LEE) of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs) has been attempted by adopting Ag-nanodots/Al reflective electrodes on a highly transparent complex p-type layer. By thinning the p-GaN to several nm, highly DUV transparent p-type layer is achieved, making it meaningful for the application of reflective electrodes composed of Ag-nanodots and Al film to allow most light emitted upward to be reflected back to the sapphire side. By this approach, the maximum light output power and external quantum efficiency of the DUV-LEDs with optimized Ag nanodots/Al electrodes are severally increased by 52% and 58%, respectively, compared to those with traditional Ni/Au electrodes when the current is below 200 mA.

Long noncoding RNA DSCAM-AS1 functions as an oncogene in non-small cell lung cancer by targeting BCL11A

OBJECTIVE

Long noncoding RNAs (lncRNAs) have attracted more attention for their role in tumor progression recently. The aim of this study was to investigate the role of DSCAM-AS1 in the progression of non-small cell lung cancer (NSCLC), and to elucidate its possible underlying mechanism.

PATIENTS AND METHODS

DSCAM-AS1 expression in both NSCLC cells and tissue samples was detected by Real Time quantitative-Polymerase Chain Reaction (RT-qPCR). Moreover, the association between the DSCAM-AS1 expression level and patients' overall survival rate was explored. Furthermore, wound healing assay and transwell assay were conducted. In addition, RT-qPCR and Western blot assay were used to elucidate the underlying mechanism.

RESULTS

DSCAM-AS1 expression level in NSCLC samples was significantly higher than that of the corresponding normal tissues. The expression level of DSCAM-AS1 was associated with an overall survival time of NSCLC patients. Besides, the migration and invasion abilities of NSCLC cells were remarkably promoted after DSCAM-AS1 overexpression in vitro. Moreover, the mRNA and protein expression of BCL11A was significantly upregulated after the overexpression of DSCAM-AS1. Furthermore, the expression of BCL11A was positively correlated with DSCAM-AS1 expression in NSCLC tissues.

CONCLUSIONS

We observed that DSCAM-AS1 could enhance NSCLC cell migration and invasion via upregulating BCL11A. Furthermore, DSCAM-AS1 might be a potential therapeutic target for NSCLC.

[Lymphocyte activation gene 3 expression on T lymphocyte cell subsets in patients with myelodysplastic syndrome]

Objective: To investigate the expression of Lymphocyte activation gene 3 (LAG3) in myelodysplastic syndromes (MDS) patients. Methods: A total of 16 MDS patients newly diagnosed in Hematology Department of Tianjin Medical University were enrolled from January to November 2019. The healthy control (HC) group includes 16 cases of healthy adults. The expression levels of LAG3 on CD8(+)T cells, CD4(+)T cells and regulatory T cells (Treg) in MDS patients and healthy controls were detected by flow cytometry. Results: A total of 16 patients with MDS were included, including 5 males and 11 females, with a median age of 56 (18-80) years old. HC group includes 16 healthy adults, 8 men and 8 women, with a median age of 40 (17-69) years. There was no statistically significant difference in gender and age composition between the two groups (both P>0.05). The expression of LAG3 on CD8(+)T cells in MDS patients (74.45%±22.31%) was significantly higher than that in HC group (58.78%±14.82%, P<0.05). The LAG3 expression on Treg in MDS patients (64.91%±10.32%) were significantly higher than that of HC group (49.09%±13.58%, P<0.05). There was no statistical difference in LAG3 expression on CD4(+)T cells between the two groups. Conclusion: The expression of LAG3 on CD8(+)T cells and Treg increases in MDS patients than that of healthy people.

Generation of low-symmetry perovskite structures for ab initio computation

Ion displacements are the fundamental cause of ferroelectricity in perovskites. By properly shifting ions, ab initio computations have been extensively used to investigate the properties of perovskites in various structural phases. In addition to the relatively simple ion displacements, perovskites have another type of structural distortion known as antiferrodistortion or oxygen octahedron tilting. The interplay between these two types of distortions have generated abundant structural phases that can be tedious to prepare for ab initio computation, especially for large supercells. Here, we design and implement a computer program to facilitate the generation of distorted perovskite structures, which can be readily used for ab initio computation to gain further insight into the perovskite of a given structural phase.

Greatly enhanced performance of AlGaN-based deep ultraviolet light emitting diodes by introducing a polarization modulated electron blocking layer

Carrier transport in AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) with the wavelength of 273 nm has been investigated by introducing polarization modulated electron blocking layer (EBL) that adopts an Al composition and thickness graded multiple quantum barriers (MQB) structure. The experimental result shows that the maximum light output power and external quantum efficiency for the proposed structure at the current of 250 mA are 9.6 mW and 1.03% respectively, severally increasing by 405% and 249% compared to traditional one, meanwhile, the efficiency droop at 250 mA is also dramatically reduced from 42.2% to 16.6%. Further simulation analysis indicates that this graded MQB-EBL enhances the potential barrier height for electrons and meanwhile reduces that for holes, hence effectively suppresses the electron leakage, and at the same time significantly improves the hole injection efficiency. As a result, the whole performance of the LED with the proposed MQB-EBL is dramatically improved.

The sapphire substrate pretreatment effects on high-temperature annealed AlN templates in deep ultraviolet light emitting diodes

Evolution of crystalline quality of AlN via high-temperature (HT) annealing induced by different sapphire pretreatments is investigated.

Realization of low dislocation density AlN on a small-coalescence-area nano-patterned sapphire substrate

Growth behaviors of AlN on hexagonal configuration hole-type and truncated-cone-pillar-type nano-patterned sapphire substrates (NPSSs) have been investigated.

Clinical application of protein biomarkers in lupus erythematosus and lupus nephritis

Systemic lupus erythematosus (SLE) is a type of autoimmune disease that damages multiple organs, including the heart, joints, liver and kidneys. The main characteristics of SLE are the deposition of circulating autoantibodies; autoantigen complexes in the renal system; and abnormal expression of complements, cytokines and chemokines. Lupus nephritis (LN) is the most serious manifestation of SLE and is characterized by inflammation of the kidney. This review summarizes recent clinical applications of protein biomarkers including autoantibodies, complements, cytokines and chemokines and some new protein biomarkers in SLE and LN. The clinical differential diagnosis of protein biomarkers related to prognosis and diagnosis is discussed and highlighted. Protein biomarkers play crucial roles in the study of SLE and LN. Useful biomarkers will provide insights into effective treatments for these diseases.

Crystal quality evolution of AlN films via high-temperature annealing under ambient N2 conditions

The crystal quality evolution of AlN films via high-temperature (HT) annealing under nitrogen is investigated.

[Pulmonary surfactant protein adenosine triphosphate-binding-cassette-A3 gene composite mutations in infant congenital interstitial lung disease: report of a case and review of literature]

Objective: To report a case of the pulmonary surfactant protein(SP) adenosine triphosphate-binding-cassette-A3 (ABCA3) gene mutations in infant congenital interstitial lung disease(ILD), and review the related literature, to investigate the relationships of ABCA3 gene mutation associated with ILD in infants. Method: A 6-months-old boy was hospitalized in the department of Pediatrics of the First Affiliated Hospital of Guangzhou Medical University. The clinical, radiological, histological information from transbronchial lung biopsy (TBLB) and genetic testing in this case was analyzed; 12 reports retrieved on literature search at Pubmed, OVID databases from 2004 to 2015 by using the ABCA3 as keyword were reviewed and analyzed. Result: (1)The patient, a 6-months-old boy, had progressive tachypnea and dyspnea since 4 months old. Physical examination on admission revealed respiratory rate of 78 times/min , heart rate of 187 times/min, SpO₂ 0.93(mask oxygen-inspiration with 6 L/min), scattered fine moist crackles could be heard over the both lungs, clubbing fingers were found. High-resolution computed tomography(HRCT) revealed diffuse ground-glass opacity, interlobular and intralobular septal thickening. Lung biopsies showed evidences of the alveolar cavity atelectatic changes and interstitial fibrosis. SP-A and SP-B were negative in immunohistochemical stainting. SP-related gene sequence analysis found that there was compound heterozygous missense mutation of ABCA3 gene in c. 1942A>G, c.2701-33G>C and c. 991-105C>A. (2)The review of related literature found that totally 12 cases were reported. The main manifestations were progressive tachypnea and dyspnea, age of onset was between birth and 4 years of age. The imaging characteristics of chest HRCT revealed diffuse infiltration or diffuse ground-glass pattern in the lung.

PROGNOSIS

6 cases died, and 6 cases survived, including 4 cases with pulmonary function disturbance to different degrees; 12 cases had ABCA3 gene mutations, 9 cases had composite ABCA3 gene mutations, in 11 cases the mutation occured in the exon of coding region, in 1 case in the intron, 9 cases had heterozygous mutations, 3 cases had homozygous mutations. Conclusion: The main phenotypes of ABCA3 mutation associated with ILD were full term neonatal respiratory distress syndrome or progressive tachypnea or dyspnea unexplained in infants. The chest HRCT showed two diffuse pulmonary interstitial changes. ABCA3 mutation mainly was multi-site composite mutations and heterozygous mutations in the exon of coding region.

Controlled-release mitomycin C-polylactic acid film prevents epidural scar hyperplasia after laminectomy by inducing fibroblast autophagy and regulating the expression of miRNAs

OBJECTIVE

To design a new controlled-release MMC-PLA film and explore whether and how this film could prevent epidural scar hyperplasia and adhesion in a post-laminectomy rat model.

MATERIALS AND METHODS

All procedures were performed under the approval and supervision of the Institutional Animal Care and Use Committee (IACUC) of Nanjing Medical University. A total of 120 Sprague-Dawley (SD) rats were randomly placed into four groups after laminectomy (each group=30 rats). In Group I, the laminectomy area was flushed with saline as a control; in Group II, 25 mg of PLA film was applied to the dura mater in the laminectomy area; in Group III, a cotton pad soaked with 0.01% MMC solution was kept on the laminectomy area; and in Group IV, 25 mg of PLA film containing 0.01% MMC was implanted on the laminectomy area. Magnetic resonance imaging (MRI), hematoxylin-eosin (HE) staining and Masson staining were used to evaluate scar adhesion and collagen deposition one month after the operation. Autophagy-related proteins, including autophagy-related gene 5 (ATG5), beclin 1, light chain-3B-2/1 (LC3B-2/1) and protein 53 (p53), were detected by Western blotting. A microRNA microarray analysis was performed to screen for scar tissue miRNAs, especially those associated with autophagy, and changes in expression were confirmed by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

A total of 112 rats recovered uneventfully from the surgery. MRI showed that the scar adhesion and scar area of the MMC-PLA group were significantly reduced compared with those of the PLA, MMC, and saline groups. Accordingly, scar adhesion and the deposition of collagen in the rats treated with MMC-PLA were also significantly reduced, as indicated by HE and Masson staining. In the scar tissue, the levels of autophagy-related proteins (ATG5, beclin 1, LC3B-2/1 and p53) were significantly elevated in the MMC-PLA group. Additionally, in the MMC-PLA group, the expression levels of miR-34a, miR-146a and miR-200 were significantly increased, while the levels of miR-16, miR-221 and miR-378a were significantly decreased.

CONCLUSIONS

The controlled-release MMC-PLA film could alleviate epidural scar hyperplasia after laminectomy; this outcome might be associated with increased autophagy and altered expression of miRNAs in the scar tissue.

Promoter Screening from Bacillus subtilis in Various Conditions Hunting for Synthetic Biology and Industrial Applications

The use of Bacillus subtilis in synthetic biology and metabolic engineering is highly desirable to take advantage of the unique metabolic pathways present in this organism. To do this, an evaluation of B. subtilis’ intrinsic biological parts is required to determine the best strategies to accurately regulate metabolic circuits and expression of target proteins. The strengths of promoter candidates were evaluated by measuring relative fluorescence units of a green fluorescent protein reporter, integrated into B. subtilis’ chromosome. A total of 84 predicted promoter sequences located upstream of different classes of proteins including heat shock proteins, cell-envelope proteins, and proteins resistant against toxic metals (based on similarity) and other kinds of genes were tested. The expression levels measured ranged from 0.0023 to 4.53-fold of the activity of the well-characterized strong promoter P43. No significant shifts were observed when strains, carrying different promoter candidates, were cultured at high temperature or in media with ethanol, but some strains showed increased activity when cultured under high osmotic pressure. Randomly selected promoter candidates were tested and found to activate transcription of thermostable β-galactosidase (bgaB) at a similar level, implying the ability of these sequences to function as promoter elements in multiple genetic contexts. In addition, selected promoters elevated the final production of both cytoplasmic bgaB and secreted protein α-amylase to about fourfold and twofold, respectively. The generated data allows a deeper understanding of B. subtilis’ metabolism and will facilitate future work to develop this organism for synthetic biology.

Local proliferation initiates macrophage accumulation in adipose tissue during obesity

Obesity-associated chronic inflammation is characterized by an accumulation of adipose tissue macrophages (ATMs). It is generally believed that those macrophages are derived from peripheral blood monocytes. However, recent studies suggest that local proliferation of macrophages is responsible for ATM accumulation. In the present study, we revealed that both migration and proliferation contribute to ATM accumulation during obesity development. We show that there is a significant increase in ATMs at the early stage of obesity, which is largely due to an enhanced in situ macrophage proliferation. This result was obtained by employing fat-shielded irradiation and bone marrow reconstitution. Additionally, the production of CCL2, a pivotal chemoattractant of monocytes, was not found to be increased at this stage, corroborating with a critical role of proliferation. Nonetheless, as obesity proceeds, the role of monocyte migration into adipose tissue becomes more significant and those new immigrants further proliferate locally. These proliferating ATMs mainly reside in crown-like structures formed by macrophages surrounding dead adipocytes. We further showed that IL-4/STAT6 is a driving force for ATM proliferation. Therefore, we demonstrated that local proliferation of resident macrophages contributes to ATM accumulation during obesity development and has a key role in obesity-associated inflammation.

HBV-induced ROS accumulation promotes hepatocarcinogenesis through Snail-mediated epigenetic silencing of SOCS3

Interleukin-6 (IL-6) has been demonstrated to be involved in Hepatitis B virus (HBV)-associated hepatocarcinogenesis through activation of the STAT3 pathway. The sustained activation of the IL-6/STAT3 pathway is frequently associated with repression of SOCS3, which is both a target gene and a negative regulator of STAT3. However, the silencing mechanism of SOCS3 in hepatocellular carcinoma (HCC) remains to be elucidated. Here, we showed that the repression of SOCS3 and sustained activation of IL-6/STAT3 pathway in HBV-producing HCC cells were caused by HBV-induced mitochondrial ROS accumulation. Mechanistic studies revealed that ROS-mediated DNA methylation resulted in the silencing of SOCS3. Decreased SOCS3 expression significantly promoted the proliferation of HCC cells and growth of tumor xenografts in mice. Further studies revealed that HBV-induced ROS accumulation upregulated the expression of the transcription factor, Snail, which bound to the E-boxes of SOCS3 promoter and mediated the epigenetic silencing of SOCS3 in association with DNMT1 and HDAC1. In addition, we found that the expression of Snail and SOCS3 were inversely correlated in HBV-associated HCC patients, suggesting that SOCS3 and/or Snail could be used as prognostic markers in HCC pathogenesis. Taken together, our data show that HBV-induced mitochondrial ROS production represses SOCS3 expression through Snail-mediated epigenetic silencing, leading to the sustained activation of IL-6/STAT3 pathway and ultimately contributing to hepatocarcinogenesis.

P53 functional abnormality in mesenchymal stem cells promotes osteosarcoma development

It has been shown that p53 has a critical role in the differentiation and functionality of various multipotent progenitor cells. P53 mutations can lead to genome instability and subsequent functional alterations and aberrant transformation of mesenchymal stem cells (MSCs). The significance of p53 in safeguarding our body from developing osteosarcoma (OS) is well recognized. During bone remodeling, p53 has a key role in negatively regulating key factors orchestrating the early stages of osteogenic differentiation of MSCs. Interestingly, changes in the p53 status can compromise bone homeostasis and affect the tumor microenvironment. This review aims to provide a unique opportunity to study the p53 function in MSCs and OS. In the context of loss of function of p53, we provide a model for two sources of OS: MSCs as progenitor cells of osteoblasts and bone tumor microenvironment components. Standing at the bone remodeling point of view, in this review we will first explain the determinant function of p53 in OS development. We will then summarize the role of p53 in monitoring MSC fidelity and in regulating MSC differentiation programs during osteogenesis. Finally, we will discuss the importance of loss of p53 function in tissue microenvironment. We expect that the information provided herein could lead to better understanding and treatment of OS.

Efficient open fermentative production of polymer-grade L-lactate from sugarcane bagasse hydrolysate by thermotolerant Bacillus sp. strain P38

Lactic acid is one of the top 30 potential building-block chemicals from biomass, of which the most extensive use is in the polymerization of lactic acid to poly-lactic-acid (PLA). To reduce the cost of PLA, the search for cheap raw materials and low-cost process for lactic acid production is highly desired. In this study, the final titer of produced L-lactic acid reached a concentration of 185 g·L⁻¹ with a volumetric productivity of 1.93 g·L⁻¹·h⁻¹ by using sugarcane bagasse hydrolysate as the sole carbon source simultaneously with cottonseed meal as cheap nitrogen sources under the open fed-batch fermentation process. Furthermore, a lactic acid yield of 0.99 g per g of total reducing sugars was obtained, which is very close to the theoretical value (1.0 g g⁻¹). No D-isomer of lactic acid was detected in the broth, and thereafter resulted in an optical purity of 100%, which exceeds the requirement of lactate polymerization process. To our knowledge, this is the best performance of fermentation on polymer-grade L-lactic acid production totally using lignocellulosic sources. The high levels of optically pure l-lactic acid produced, combined with the ease of handling and low costs associated with the open fermentation strategy, indicated the thermotolerant Bacillus sp. P38 could be an excellent candidate strain with great industrial potential for polymer-grade L-lactic acid production from various cellulosic biomasses.

Genetic diversity based on SSR analysis of the cultured snakehead fish, Channa argus, (Channidae) in China

The snakehead fish Channa argus is an important food fish in China. We identified six microsatellite loci for C. argus. These six microsatellite loci and four other microsatellite markers were used to analyze genetic diversity in four cultured populations of C. argus (SD, JX, HN, and ZJ) and determine their relationships. A total of 154 alleles were detected at the 10 microsatellite loci. The average expected and observed heterozygosities varied from 0.70-0.84 and 0.69-0.83, respectively, and polymorphism information content ranged between 0.66 and 0.82 in the four populations, indicating high genetic diversity. Population JX deviated from mutation-drift equilibrium and may have experienced a recent bottleneck. Analysis of pairwise genetic differentiation revealed FST values that ranged from 0.028 to 0.100, which indicates a moderate level of genetic differentiation. The largest distances were observed between populations HN and SD, whereas the smallest distances were obtained between populations HN and JX. Genetic clustering analysis demonstrated that the ZJ and HN populations probably share the same origin. This information about the genetic diversity within each of the four populations, and their genetic relationships will be useful for future genetic improvement of C. argus through selective breeding.

Immunobiology of mesenchymal stem cells

Mesenchymal stem cells (MSCs) can be isolated from almost all tissues and effectively expanded in vitro. Although their true in situ properties and biological functions remain to be elucidated, these in vitro expanded cells have been shown to possess potential to differentiate into specific cell lineages. It is speculated that MSCs in situ have important roles in tissue cellular homeostasis by replacing dead or dysfunctional cells. Recent studies have demonstrated that in vitro expanded MSCs of various origins have great capacity to modulate immune responses and change the progression of different inflammatory diseases. As tissue injuries are often accompanied by inflammation, inflammatory factors may provide cues to mobilize MSCs to tissue sites with damage. Before carrying out tissue repair functions, MSCs first prepare the microenvironment by modulating inflammatory processes and releasing various growth factors in response to the inflammation status. In this review, we focus on the crosstalk between MSCs and immune responses and their potential clinical applications, especially in inflammatory diseases.

[Optimization of succinic acid fermentation with Actinobacillus succinogenes by response surface methodology]

Succinic acid is an important C4 platform chemical in the synthesis of many commodity and special chemicals. In the present work, different compounds were evaluated for succinic acid production by Actinobacillus succinogenes GXAS 137. Important parameters were screened by the single factor experiment and Plackeet-Burman design. Subsequently, the highest production of succinic acid was approached by the path of steepest ascent. Then, the optimum values of the parameters were obtained by Box-Behnken design. The results show that the important parameters were glucose, yeast extract and MgCO3 concentrations. The optimum condition was as follows (g/L): glucose 70.00, yeast extract 9.20 and MgCO3 58.10. Succinic acid yield reached 47.64 g/L at the optimal condition. Succinic acid increased by 29.14% than that before the optimization (36.89 g/L). Response surface methodology was proven to be a powerful tool to optimize succinic acid production.

Tumebacillus flagellatus sp. nov., an α-amylase/pullulanase-producing bacterium isolated from cassava wastewater

A novel α-amylase/pullulanase-producing bacterium, designated strain GST4T, was isolated from samples collected from the wastewater of a cassava starch factory in Nanning, Guangxi Autonomous Region, southern China. Cells of strain GST4T were rod-shaped bacilli containing ellipsoidal terminal spores and found to be Gram-reaction-positive, aerobic, motile, oxidase-positive, catalase-negative and formed light yellow colonies on agar plates. Strain GST4T was able to grow at pH 4.5–8.5 (optimum at pH 5.5), temperatures ranging from 20 to 42 °C (optimum at 37 °C) and salt concentrations of 0–1 % (w/v) NaCl (optimum at 0.5 %, w/v) on R2A medium. Strain GST4T grew heterotrophically on complex carbon substrates and chemolithoautotrophically on inorganic sulfur compounds, as demonstrated by growth on sodium thiosulfate and sulfite as sole electron donors. It can reduce nitrate and nitrite. Strain GST4T contained iso-C15 : 0 and anteiso-C15 : 0 as the major cellular fatty acids and menaquinone 7 (MK-7) as the major respiratory quinone. The cell-wall peptidoglycan was of type A1γ. The genomic DNA G+C content of strain GST4T was 53.7 mol%. Physiological and chemotaxonomic characteristics combined with phylogenetic analysis based on 16S rRNA gene sequences revealed that strain GST4T was a member of the genus Tumebacillus and most closely related to Tumebacillus permanentifrigoris DSM 18773T and Tumebacillus ginsengisoli DSM 18389T with 97.3 and 94.5 % sequence similarity, respectively. The DNA–DNA relatedness values between strain GST4T and T. permanentifrigoris DSM 18773T, and strain GST4T and T. ginsengisoli DSM 18389T were 44.0 and 60.4 %, respectively. The new isolate differed from those species of the genus Tumebacillus in that it has peritrichous flagella for motility. Based on the evidence obtained from this study, strain GST4T represents a novel species of the genus Tumebacillus , for which the name Tumebacillus flagellatus sp. nov. is proposed. The type strain is GST4T ( = CGMCC 1.12170T = DSM 25748T).

Association of Gln223Arg polymorphism of the leptin receptor with hypertensive left ventricular hypertrophy

This study was aimed to determine whether the leptin receptor Gln223Arg polymorphism has an effect on plasma leptin levels and left ventricular hypertrophy in hypertension. The genotypes and allelic frequencies of the leptin receptor Gln223Arg were examined using the polymerase chain reaction and restriction fragment length polymorphism in 190 hypertensive patients and 88 healthy controls. Logarithmic (log) transformation of the plasma leptin level was carried out before performing comparison and regression analysis. The values of log(plasma leptin levels) in the hypertensive patients were higher than those of controls and they were higher in hypertensive patients with left ventricular hypertrophy than those without it (P < 0.05). The genotype (AA, AG, and GG) distribution of Gln223Arg polymorphism was 6.8, 33.8, and 59.4% in hypertensive patients with left ventricular hypertrophy, 4.3, 27.6, and 68.1% in patients without left ventricular hypertrophy, and 2.3, 26.1, and 71.6% in the controls, respectively. A significant difference was found among these three groups (P < 0.05). The frequency of allele A was higher in patients with left ventricular hypertrophy than in patients without it (23.6 vs. 18.1%; P < 0.05). Log(plasma leptin levels) and left ventricular mass index were higher in patients with the AA genotype than those with the AG or GG genotype in hypertensive patients (P < 0.05). In multivariate regression analysis, the AA genotype as an independent predictor had statistically significant effects on the left ventricular mass index. Our results suggest that the Gln223Arg polymorphism of the leptin receptor is significantly associated with plasma leptin levels and left ventricular hypertrophy in hypertension.