Isolation, identification and heavy metals biosorption of a lead and cadmium-tolerant strain / 生物工程学报

Adding biological passivation agent during composting is one of the most effective ways to reduce the toxicity of heavy metals in contaminated livestock manure. To further improve biological passivation, we obtained a strain with high-heavy metal compounds tolerance to passivate heavy-metal contaminated manure and to characterize heavy-metal biosorption. High-tolerance microorganisms for lead and cadmium were isolated and screened from swine manure composting samples. The strain was identified by its morphology and molecular biology. After the influence of different pH, temperature and salt concentrations on growth of the strain were investigated, the optimal growth conditions were obtained for further analysis of its biosorption characteristics of lead and cadmium. The bacterium with tolerance to lead and cadmium termed SC19 was obtained, whose lead resistance was 600 mg/L and cadmium resistance was 120 mg/L. The isolate was further identified as Cedecea sp., and then its optimum pH was 7.0, temperature was 37 °C, and salt concentration was 0.5%. Lead removal was highest after 30 min of adsorption by the SC19 strain cultured for the stationary phase 36 h, and the maximum removal rate and biosorption capacity of lead were 60.7% and 329.13 mg/g, respectively. Meanwhile, cadmium removal was highest after 30 min of adsorption by the strain cultured for the logarithmic phase 8 h, and the maximum removal rate and biosorption capacity of cadmium were 51.0% and 126.19 mg/g, respectively. Fourier Transform InfraRed (FT-IR) results revealed that the biosorption process mainly happened on the surface of SC19 cell and many active groups on the cell surface could chelate the Pb²⁺ and Cd²⁺. By comprehensive comparison, it was showed that strain SC19 shared a certain capacity of Pb²⁺ and Cd²⁺ biosorption, and the bacterium provided precious microbial germplasm resources for biological passivation of heavy metal contaminated manure.

Comparison of the effect of small incision cataract surgery whether combined with nucleus chopping or not in the treatment of cataract / 中国基层医药

Objective To compare efficacy of small incision cataract surgery whether combined with nucleus chopping or not in the treatment of cataract. Methods From March 2014 to September 2015,125 cases of age-related cataract(146 eyes) in the the First People′s Hospital of Xiantao were divided into 60 cases(75 eyes) of observation group and 65 cases(71 eyes) of control group by method of random sampling. The observation group accepted small incision cataract surgery combined with chopping nucleus. The control group only underwent small incision cataract surgery. The postoperative visual acuity,corneal astigmatism and operation time,and complications and so on in the two groups were compared. Results There was statistically significant difference in postoperative visual acuity after 1 week between the two groups(Z = -2. 078,P <0. 05),but there was no statistically significant difference in postoperative visual acuity after 1 month or 3 months between the two groups(Z= -0. 960,-0. 743,all P>0. 05). The postoperative corneal astigmatism after 1 week or 1 month between the observation group and the control group had statistically significant differences[(1. 33 ± 0. 45) D vs. (1. 52 ± 0. 49) D,(1. 03 ± 0. 42) D vs. (1. 18 ± 0. 44)D,t=2. 442,2. 108,all P<0. 05)],but there was no statistically significant difference in postoperative corneal astigmatism after 3 months between the two groups(t =0. 432,P >0. 05). There was no statistically significant difference in the operation time between the observation group and the control group[(11. 28 ± 2. 32) min vs. (11. 87 ± 2. 52)min,t=1. 473,P>0. 05]. One case of posterior capsular rupture occurred in the two groups,respec-tively. But serious complications such as lens nucleus escaped into vitreous cavity, explosive haemorrhage from the choroid or corneal endothelial decompensated had not been found. Conclusion The small incision cataract surgery combined with nucleus chopping has advantages in acquiring fast visual rehabilitation acuity in the early stage after operation,lower corneal astigmatism compared to that without nucleus chopping. Therefore,the small incision cataract surgery combined with nucleus chopping is worthy of clinical popularization and application.

Expression of midkine and microvessel density in salivary adenoid cystic carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to investigate the expression of midkine (MK) and microvessel density (MVD) in patients with salivary adenoid cystic carcinoma (SACC) and its clinical significance, as well as detect the correlation between the expression of MK and MVD in SACC.</p><p><b>METHODS</b>Immunohistochemistry analysis (SP method) for MK and MVD were performed on 60 cases of SACC and 26 cases of normal salivary gland tissue. The expression of MK and MVD, as well as the correlation between the expression of MK and MVD in SACC were detected.</p><p><b>RESULTS</b>In SACC, the MK expression rate was 70.0% (42/60), and MK was not expressed in normal tissue. Statistical significance was found between SACC and normal tissue (P<0.05). The MVD values in SACC and normal salivary gland tissues were 38.73 +/- 8.96 and 11.15 +/- 3.33, respectively. These values were statistically significant (P<0.05). The expression levels of MK and MVD were unrelated to age, gender, and type in SACC (P>0.05), but correlated with tumor size, lymph node metastasis, and tumor-node-metastasis in SACC (P<0.05). The expression of MK and MVD was positively correlated with SACC (r=0.560, P<0.05).</p><p><b>CONCLUSION</b>SACC is correlated with the expression of MK protein and the increase in MVD, which may be some of the early diagnostic markers in SACC.</p>

Osteogenetic ability of mouse spermatogonial stem cells cultured in vitro / 中国组织工程研究

BACKGROUND:Spermatogonial stem cells are a kind of adult stem cells, which have self-renewal and differentiation potential, and can be differentiated into specific cells in vitro, suggesting that the spermatogonial stem cells may be possibly differentiated into osteoblasts. But the related research has not been reported. OBJECTIVE:To observe the biological characterization and osteogenic process of mouse spermatogonial stem cells cultured in vitro. METHODS:Spermatogonial stem cells were obtained from the testicle of mice aged 15-20 days, and were cultured on the feeder layer from bone marrow stroma cells in vitro. When cultured for 3 days, the cells were cultured in the conditioned medium (experimental group) and basic medium (control group). The cells proliferation capability and osteogenic property were examined by phase-contrast microscope, alkaline phosphatase activity and type I col agen immunofluorescence staining. RESULTS AND CONCLUSION:Spermatogonial stem cells proliferated faster in the experiment group than in the control group. cells grew rapidly in colony-like shape in the conditioned medium at 3-6 days, the three-dimensional feeling enhanced, cellmass and clusters continued to increase in size, the extracellular matrix was increased in number and the cytoplasmic bridge was not obvious. After culture for 15 days, cells in the two groups were positive for alkaline phosphatase staining that the cytoplasmic membrane was dyed black. Under the fluorescent microscope, green fluorescence was visible in the experimental group, suggesting the cells in the experimental group was positive for type I col agen, but negative in the control group, which is similar with the biological characteristics of osteoblasts. These findings indicate that spermatogonial stem cells possess the osteogenic capability under induction conditions, which are expected to provide seed cells for bone tissue engineering.

Inhibitory effects of nm23-H1 gene on proliferation and invasion of A549 cell line / 中国病理生理杂志

AIM: To study the inhibitory effects of nm23-H1 gene on proliferation and invasion of human lung adenocarcinoma A549 cell line. METHODS: Recombinant eukaryotic expression vector pcDNA3.1-nm23-H1 containing full length of human nm23-H1 cDNA was constructed and transfected into a human lung adenocarcinoma A549 cell line by lipofectamine. Cell strain that expressed nm23-H1 stably was screened out by G418 and named pcDNA-nm23-A549. Expression of nm23-H1 was identified by RT-PCR and immunohistochemistry. Growth curves were drawn to detect the inhibitory effects on cell proliferation. Cell cycle of pcDNA-nm23-A549 was examined by flow cytometry. Atomic force microscopy was used to observe the filopodia on the surface of the cells. RESULTS: Introduction of nm23-H1 obviously inhibited the proliferation of A549. Expression of nm23-H1 did not induce apotosis in A549 cells but increased the percentage of phase G_1 cells and decreased phase S cells. Meanwhile, phase G_1 to phase S transition was restrained. Filopodia in the cell surface was much fewer and its structure changed in cells transformed. CONCLUSION: nm23-H1 is capable of inhibiting A549 proliferation and decreasing its metastatic ability, probably by interfering with cell cycle and cell surface structure.