Arsenic is known as a toxic metalloid, which mainly exists in inorganic forms such as arsenite and arsenate in the natural environment. A number of microorganisms have evolved different resistant mechanisms for arsenic detoxification to cope with the widespread distribution of the poisonous arsenic. Four distinct microbial arsenic-resistant mechanisms have been described including As(III) oxidation, cytoplasmic As(V) reduction, respiratory As(V) reduction, and As(III) methylation. These mechanisms confer arsenic resistance in microorganisms that play important roles in the transformation and geological cycle of arsenic. This review mainly focuses on the researches on these molecular mechanisms and potential application for environmental arsenic bioremediation using microorganisms.

BACKGROUND:Studies have shown that simvastatin can promote bone formation, but there is stil controversial on the osteogenic mechanism and osteogenic effect.
OBJECTIVE:To explore the osteogenesis effect of the composite of simvastatin and Bio-Oss versus simple Bio-Oss material on the repair of rabbit mandibular defects.
METHODS:Twelve New Zealand white rabbits were selected to establish alveolar bilateral mandibular defects models. The composite of simvastatin and Bio-Oss was implanted randomly in one side of defect region;Bio-Oss was simply implanted in the other side of defect region. Both sides were covered with Bio-Gide bilayer col agen membrane. Four rabbits in each group were sacrificed at 4, 8 and 12 weeks after implantation, and the general observation X-ray film, oral cone-beam CT imaging observation and histopathologic study and quantitatively were conducted to quantitatively and qualitatively comparative analyze the alveolar bone formation in the graft region.
RESULTS AND CONCLUSION:At 4, 8 and 12 weeks after implantation, new bone formation was found and increased with time prolonging. With the gradual degeneration of high resistance fire Bio-Oss bone meal, the bone mineral density at different time points of the simvastatin composite Bio-Oss group was lower than that of the simple Bio-Oss group (P<0.05). The percentage of bone formation in the simvastatin composite Bio-Oss group was significantly higher than that in the simple Bio-Oss group (P<0.05). Simvastatin could accelerate Bio-Oss degradation and promote new bone formation in bone defects repairing.

Manganese-oxidizing microorganisms are able to oxidize soluble Mn(II) into insoluble Mn oxides. Such microorganisms are very useful in treatment of Mn-contaminated water. In this research, a Mn(II)- oxidizing bacterium Bacillus sp. MK3-1 was isolated from Mn-contaminated soil. This bacterium has high MnCl2 resistance with a MIC of 20 mmol/L. The results showed that it is able to oxidize and remove more than 96% of Mn(II) in the culture medium. The immobilized solid-embedding Bacillus sp. MK3-1can re- moved 87.12% of manganese contaminated water. The final concentration of MnCl2 after the treatment reached the national discharge standard level. Scan electron microscope observation showed that the pro- duced Mn oxides located on the cell surfaces of Bacillus sp. MK3-1. Energy dispersive spectrdmeter analy- sis indicated that the content of manganese of cell surfaces of Bacillus sp. MK3-1 was 19.60% (W/W). At last we amplified a 903 bp multicopper oxidase gene mnxG encoding the putative Mn(II)-oxidizing protein.The product of mnxG showed 86% identity to the reported multicopper oxidase.

BACKGROUND:Studies have found that the platelet-rich plasma (PRP) can promote bone and soft tissue injury repair, but its effect on the process of bone healing is stil controversial.
OBJECTIVE:To contrastively observe the osteogenesis effect of PRP/Bio-Oss/Bio-Gide in the repair process of alveolar bone defect in rabbits, so as to explore the role of PRP in bone healing.
METHODSixteen New Zealand white rabbits were used to establish animal models of critical-size alveolar bone defect. One side was damaged randomly and repaired by PRP/Bio-Oss/Bio-Gide as experimental side, and the other side repaired by Bio-Oss/Bio-Gide as control side. Four animals were executed at each time-point, postoperative weeks 2, 4, 8, 12. Through general observation, X-ray radiograph, Cone Beam CT assessment, histological examination, the osteogenesis effect in the defect region was qualitatively and quantitatively analyzed.
RESULTS AND CONCLUSION:It could be know from each observation index that as time went on, the experimental and control sides had a different degree of new bone formation and the degradation-absorption of bone graft material. At 12 weeks, continuous cortical bone formation was seen on the surface of the experimental side, new bone formed and tended to be mature, obvious degradation of the bone graft was found, but those in the control side were not as good. At each time-point of 2, 4, 8, 12 weeks, the bone mineral density of the experimental side were lower than that of the control side (P<0.05), but the percentage of new bone area was larger than in the experimental side than the control side (P<0.05). These findings indicate that the PRP/Bio-Oss/Bio-Gide has a better osteogenesis effect than the Bio-Oss/Bio-Gide in the repair process of alveolar bone defect in rabbits, and PRP can promote new bone formation and degradation-absorption of Bio-Oss.

Neurogenesis is a process in which the neuronal stem cells differentiate into functional neurons including the cell proliferation,differentiation and migration.Previously,it was believed that neurogenesis is a prenatal process and the adult ependymal cells are incapable of regeneration.Now it is clear that mammalian brain retains the ability to generate new ceils in specific regions.One of the regions is subventricular zone of the lateral ventricles,new generated neurons and glial cells later migrate to olfactory and repair dysosmia through the RMS road.Here we will review the advances in adult neurogenesis in mammal subventficular zone.

Halophilic microorganisms play important rules in salt field ecosystem and salt production. In this study, halophilic bacteria and haloarchaea from soils of Lianyungang Taibei and Yancheng Sanwei salt fields were analyzed. The halophilic bacterial and haloarchaeal types from both the soils were similar, but each soil had its distinctive species. A total of 17 halophilic bacteria were identified, among them, Halomonas was found from both the soils, while Pontibacillus and Halobacillus were isolated from Sanwei salt field only. Using uncultured 16S rRNA gene library technology, 13 haloarchaeal soil 16S rRNA genes were identified from both the saline soils. Halobacterium and Haloplanus were found from Taibei salt field, while Halobac- terium, Natronobacterium, Halogeometricum and Haloarcula were identified from Sanwei salt field. Ten haloarchaeal 16S rRNA gene sequences showed 92%~97% identities with the GenBank sequences that ap- pear to represent novel soil haloarchaeal species. This study provides important information that is useful for further investigation and application of halophiles of saline soil fields.

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer, and its micrometastases are commonly seen in clinical practice. Although great progress has been made in immunotherapy for malignancies in recent years, immune checkpoint blockade focusing on programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) has changed the clinical diagnosis and treatment of non-small cell lung cancer, melanoma, urothelial carcinoma, and renal carcinoma. However, the clinical effect of immunotherapy in PDAC is limited by the low immunogenicity and unique tumor microenvironment (TME) of PDAC. With the research advances in PDAC-TME, an in-depth analysis of the highly complex interaction network between immune system, tumor cell, and matrix signal may help to develop a rational combination of immunotherapies for PDAC. By elaborating on the unique immunological features of PDAC-TME, this article reviews the potential treatment opportunities for PDAC and the advances in clinical research.

Objective:To investigate the mechanism of programmed death 1(PD-1)/ programmed death ligand 1(PD-L1) signaling pathway and its feasibility as a potential therapeutic target and prognostic predictor by detecting the expressions, of PD-1 and PD-L1 in bone marrow mononuclear cells of children with acute lymphoblastic leukemia (ALL), and to provide new ideas for the diagnosis and treatment of ALL as well.Methods:Bone marrow samples were collected from 59 children with ALL in the First Affiliated Hospital of Zhengzhou University from September 2018 to July 2019.Flow cytometry was applied to detect the expression of PD-1 and PD-L1 in bone marrow mononuclear cells in 59 ALL patients, including 47 newly-diagnosed ALL patients and 12 relapsed ALL patients, respectively, at initial diagnosis, after induction therapy and early intensive treatment.Their relevant clinical data were collected and compared with the bone marrow specimens of 12 children suffering from non-malignant blood diseases as the control group of the same hospital during the same period.Results:There was no significant difference in the expression of PD-1 in the bone marrow mononuclear cells of the primary diagnosis group, recurrence group and control group ( H=2.402, P>0.05). The expression of PD-L1 in the relapsed and refractory group [(7.32±3.60)%] and the newly diagnosed group [(3.18±2.37)%] was higher than that in the control group [(0.84±0.39)%], and the differences were statistically significant ( H= 28.048, P<0.05). In the initial treatment group, the expression of PD-L1 in the bone marrow mononuclear cells was the strongest expression before treatment ( B=1.293), followed by after induction treatment ( B=0.036) and after early intensive treatment ( B=0.000), suggesting that there was a downward trend as the continued treatment.The expression of PD-L1 was the weakest expression in the low-risk group ( B=-3.912) than in the medium-risk group ( B=-3.595) and high-risk group ( B=0.000), revealing that the expression of PD-L1 is related to the risk grades of ALL.The higher the risk rating is, the higher the PD-L1 protein expression is. Conclusions:The high expression of PD-L1 may be involved in the pathogenesis and be used as an adverse predictor of ALL childhood and an evaluation index of chemotherapy efficacy.PD-1 / PD-L1 signaling pathway may be a potential therapeutic target of ALL childhood.

Objective To prepare and study the immunogenicity of hepatitis B virus surface anti-gen (HBsAg)-tetanus toxoid (TT) conjugate vaccine. Methods Tr was activated by cyangen bromide and reacted with adipic acid dihydrazide, then HBsAg-TT conjugate was prepared by carbediimide. Conjugate, HBsAg or hepatitis B vaccine was injected subcutaneously into mice. Anti-HBsAg and HBsAg-specific T cell response elicited by these immunogens were assayed. Results New HBsAg-TT conjugate elicited higher levels of anti-HBsAg and HBsAg positive conversion rates after the immunization than did HBsAg alone or hepatitis B vaccine. Conjugate induced mesdy antibodies of the IgG2a subclass, while HBsAg alone or hepa-titis B vaccine mainly elicited anti-HBsAg in the IgG1 subclass. The number of IFN-γand IL-2 secreting T cells induced by conjugate was also significantly higher than that did by HBsAg or hepatitis B vaccine. Con-clusion This study indicated new HBsAg-TT conjugate can induce both stronger humoral and TH1 type of cellular immune response.

Objective:To observe the effect of electromyographic biofeedback on the wrist dirsiflexion function of the patients with cerebral infarction at different Brunnstrom stages, and to clarify the treatment of electromyographic biofeedback,and to provide basis for its clinical application.Methods:A total of 100 cerebral infarction patients were selected.Among them 54 BrunnstromⅠ-Ⅱ patients were randomly divided into treatment group (n= 32)and control group (n = 22),and another 46 Brunnstrom Ⅲ patients were randomly divided into treatment group (n=23)and control group (n=23).The patients in four groups were treated with the same routine stroke rehabilitation therapy while the patients in treatment groups still received the electromyographic biofeedback therapy additionally.The maximum electromyographic contraction of muscle,active range of movement (AROM) and Fugl-Meyers Assessment (FMA)of the extension of wrist joint were evaluated before treatment and 4 and 8 weeks after treatment,respectively.Results:The maximum electromyographic contraction values of muscle of the patients in BrunnstromⅠ-Ⅱ treatment group and control group were significantly improved 8 weeks after treatment (P <0.05),and the value in treatment group was higher than that in control group (P <0.05).The maximum electromyographic contraction value of muscle in Brunnstrom Ⅲ treatment group began to improve 4 weeks after treatment compared with before treatment (P < 0.05) and it was significantly higher than that in control group (P <0.05).The maximum electromyographic contraction value of muscle in Brunnstrom Ⅲ control group began to improve 8 weeks after treatment (P <0.05).The AROM in Brunnstrom Ⅰ-Ⅱ treatment group began to improve 8 weeks after treatment (P <0.05)and it was significantly higher than that in control group (P <0.05)while the AROM in control group had no significant change (P >0.05).The AROM in Brunnstrom Ⅲ treatment group and control group were significantly improved 4 weeks after treatment (P < 0.05 or P < 0.01 ), and the value in treatment group was significantly higher than that in control group (P < 0.05).The FMA in BrunnstromⅠ-Ⅱtreatment group and control group were significantly improved 8 weeks after treatment (P <0.05),while the value in treatment group was higher than that in control group (P <0.05);the FMA in Brunnstrom Ⅲ treatment group began to improve 4 weeks after treatment (P < 0.05)and it was significantly higher than that in control group (P <0.05). The FMA in control group began to improve 8 weeks after treatment (P <0.05). Conclusion:Electromyographic biofeedback can increase the strength and improve the body function of the patients with cerebral infaction.