CRISPR/Cas(the clustered regularly interspaced short palindromic repeats-CRISPR associated)system exists in most bacteria and all archaea. It is an important strategy for bacteria and archaea to resist foreign nucleic acid invasion and use for self-defense. The CRISPR/Cas system is a simple, fast, and specific diagnostic tool, which is widely used in agriculture, industry, animal husbandry, and medicine. This article mainly introduces and discusses recently advantages and limitations of biosensors combining CRISPR/Cas system with fluorescence, visualization and surface enhanced raman related technologies, as well as future research directions.
Animals ; CRISPR-Cas Systems ; Bacteria/genetics* ; Archaea

OBJECTIVES: To investigate the clinical treatment outcomes and the changes of the outcomes over time in extremely preterm twins in Guangdong Province, China. METHODS: A retrospective analysis was performed for 269 pairs of extremely preterm twins with a gestational age of <28 weeks who were admitted to the department of neonatology in 26 grade A tertiary hospitals in Guangdong Province from January 2008 to December 2017. According to the admission time, they were divided into two groups: 2008-2012 and 2013-2017. Besides, each pair of twins was divided into the heavier infant and the lighter infant subgroups according to birth weight. The perinatal data of mothers and hospitalization data of neonates were collected. The survival rate of twins and the incidence rate of complications were compared between the 2008-2012 and 2013-2017 groups. RESULTS: Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of severe asphyxia and smaller head circumference at birth (P<0.05). The mortality rates of both of the twins, the heavier infant of the twins, and the lighter infant of the twins were lower in the 2013-2017 group compared with the 2008-2012 group (P<0.05). Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of pulmonary hemorrhage, patent ductus arteriosus (PDA), periventricular-intraventricular hemorrhage (P-IVH), and neonatal respiratory distress syndrome (NRDS) and a higher incidence rate of bronchopulmonary dysplasia (P<0.05). CONCLUSIONS There is a significant increase in the survival rate over time in extremely preterm twins with a gestational age of <28 weeks in the 26 grade A tertiary hospitals in Guangdong Province. The incidences of severe asphyxia, pulmonary hemorrhage, PDA, P-IVH, and NRDS decrease in both the heavier and lighter infants of the twins, but the incidence of bronchopulmonary dysplasia increases. With the improvement of diagnosis and treatment, the multidisciplinary collaboration between different fields of fetal medicine including prenatal diagnosis, obstetrics, and neonatology is needed in the future to jointly develop management strategies for twin pregnancy.
Bronchopulmonary Dysplasia/epidemiology* ; Female ; Gestational Age ; Humans ; Infant ; Infant, Extremely Premature ; Infant, Newborn ; Pregnancy ; Respiratory Distress Syndrome, Newborn/epidemiology* ; Retrospective Studies ; Treatment Outcome

OBJECTIVETo study the relationship between the levels of erythropoietin (EPO) in serum and brain injury in preterm infants.

METHODSThree hundred and four preterm infants (gestational age: 28-34 weeks) born between October 2014 and September 2015 were enrolled in this study. Brain injury was diagnosed using cerebral ultrasound and MRI. The levels of EPO, S100 protein, neuron-specific enolase (NSE) and myelin basic protein (MBP) in serum were detected using ELISA. To compare the incidence of brain injury in different serum EPO levels in preterm infants, and the relationship between brain injury and serum EPO levels was analyzed.

RESULTSThe incidence rate of brain injury in preterm infants was 41.1% (125/304). The incidence rate of brain injury in the low EPO level group was significantly higher than that in the middle-high EPO level groups (P<0.01). The serum levels of S100 protein, NSE, and MBP in the brain injury groups were significantly higher than in the control group (P<0.01). The serum EPO levels were negatively correlated with serum S100 protein concentration and NSE levels (P<0.05). According to the multiple logistic regression analysis, low gestational age, low birth weight, asphyxia, prolonged mechanical ventilation, anemia and low serum EPO levels were the risk factor for brain injury in preterm infants.

CONCLUSIONSThere is a higher incidence rate of brain injury in preterm infants with lower serum EPO levels. The serum EPO levels may be correlated with brain injury in preterm infants.

Brain Injuries ; blood ; epidemiology ; Erythropoietin ; blood ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; blood ; Male ; Myelin Basic Protein ; blood

OBJECTIVELcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study.

METHODSA new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a. After Co(2+) affinity chromatography, a purification strategy was developed by cleavage of His tag on column, following Sephacryl S-200HR column filtration chromatography.

RESULTSRemoval of His tag by thrombin, enterokinase and factor Xa displayed a yield of 99.5%, 32.4% and 15.3%, respectively. Following Sephacryl S-200HR column filtration chromatography, above 97% purity of rV270 protein was obtained. Purified rV270 that was adsorbed to 25% (v/v) Al(OH)₃ adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to rV270 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 10⁶ CFU of Y. pestis virulent strain 141.

CONCLUSIONThe completely authentic rV270 protein can be prepared by using enterokinase or factor Xa, but they exhibited extremely low cleavage activity to the corresponding recognition site. Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy. The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.

Amino Acid Sequence ; Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; genetics ; immunology ; Blotting, Western ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Female ; Genetic Vectors ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Plague ; immunology ; prevention & control ; Plague Vaccine ; genetics ; immunology ; Plasmids ; Pore Forming Cytotoxic Proteins ; genetics ; immunology ; Protein Engineering ; methods ; Recombinant Fusion Proteins ; genetics ; immunology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Survival Analysis ; Vaccines, Subunit ; genetics ; immunology ; Yersinia pestis ; growth & development ; immunology

OBJECTIVETo evaluate the protective efficacy of plague subunit vaccine, BALB/c mice, guinea pigs and rabbits were used in this study.

METHODSGroups of mice (10 per group), guinea pigs (14 per group) and rabbits (6 per group) were immunized with F1 + rV270 vaccine, EV76 vaccine and alum adjuvant by intramuscular route, respectively. Serum antibody titres of mice, guinea pigs and rabbits were determined by ELISA and the immunized animals were challenged with 10(6) CFU of Y. pestis strain 141 at the 8th week after the primary immunization.

RESULTSThe immunized mice, guinea pigs or rabbits with subunit vaccine developed anti-F1 IgG titre of 41 587.3 +/- 2.1, 11 543.7 +/- 2.1 or 522.4 +/- 22.4 and elicited statistical anti-F1 IgG titre difference among them (F = 17.58, P < 0.01). The immunized mice, guinea pigs or rabbits with subunit vaccine had anti-rV270 IgG titre of 15 748.7 +/- 1.6, 12.6 +/- 1.4 or 1648.0 +/- 5.0 and induced statistical anti-rV270 IgG titre difference among them (F value was 16.34, P < 0.01). There was significant anti-F1 IgG titre difference among mice, guinea pigs and rabbits immunized with EV76 vaccine that developed anti-F1 IgG titre of 913.4 +/- 4.5, 937.0 +/- 2.0 or 342.0 +/- 12.0 (F = 23.67, P < 0.01), whereas the immunized mice, guinea pigs and rabbits with EV76 vaccine developed anti-rV270 IgG titre of 12.0 +/- 1.0, 447.0 +/- 10.0, 40.0 +/- 11.0 and there was no anti-rV270 IgG titre difference between them (F = 2.20, P = 0.1314). The immunized mice with subunit vaccine developed significantly higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 30.57 and 19.04, respectively, P < 0.01), and there were no anti-F1 IgG titre differences between the immunized guinea pigs and rabbits (q = 0.04, P = 0.8485). The immunized mice with subunit vaccine developed significantly higher anti-rV270 IgG titres than immunized guinea pigs and rabbits (q value was 27.10 and 19.49, respectively, P < 0.01), and there were no anti-rV270 IgG titre differences between the immunized guinea pigs and rabbits with the subunit vaccine (q = 0.25, P = 0.6187). The immunized mice with EV76 elicited higher anti-F1 IgG titres than immunized guinea pigs and rabbits (q value was 40.67 and 29.10, respectively, P < 0.01), whereas there was no difference of F1 IgG titer between immunized guinea pigs and rabbits (q = 0.06, P = 0.8098). The immunized mice, guinea pigs and rabbits with subunit vaccine provided 100% (10/10), 86% (12/14) and 100% (5/5) protection against 10(6) CFU Y. pestis of challenge, respectively. The immunized mice, guinea pigs and rabbits with EV76 vaccine gave 100% (6/6), 93% (13/14) and 100% (6/6) protection against 10(6) CFU Y. pestis of challenge respectively.

CONCLUSIONBALB/c mice is the best small animal model for valuation of protective efficacy of plague subunit vaccine. The guinea pigs showed a high individual variation for this purpose. The rabbits can be used as an alternative model for evaluating plague subunit vaccine.

Animals ; Antibodies, Bacterial ; blood ; Dose-Response Relationship, Immunologic ; Female ; Guinea Pigs ; Immunization ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Models, Animal ; Plague ; prevention & control ; Plague Vaccine ; immunology ; Rabbits ; Vaccines, Subunit ; immunology

OBJECTIVETo evaluate the effect of snail control through soil pasting mixed with niclosamide.

METHODSFour sites were selected in different epidemic areas in Sichuan province. Soil pasting mixed with niclosamide was carried on, and the dosage was 0 g/m2, 4 g/m2, 6 g/m2, 8 g/m2 and 10 g/m2 respectively. The mortality rate of snail and the density of snail were observed after 7, 15, 30, 90 and 180 days.

RESULTSThe mortality rate of snail was more than 43.3% in blank group after 30 days. The mortality rate of snail was from 75.3% to 100.0% at 4 g/m2 group after 30 days. The mortality rate of snail in 4 g/m2 group was significantly higher than that in the blank group (chi2 = 31.27, P < 0.05). There was no significant difference in the mortality rate of snail among all study groups (chi2 = 1.07, P > 0.05). The decrease rate of snail density was more than 90%. The mortality rate of snail was about 30% higher in Chantu group than Qutu group. The unit cost of Pasting-Mixing Drug with Soil was from 5 to 7 times of spray method, but the total cost was similar for the. two methods at the endpoint of the snail control.

CONCLUSIONThe effect of soil pasting mixed with niclosamide is good, and the dosage of 4-6 g/m2 is suggested in snail control.

Animals ; Molluscacides ; Niclosamide ; Pest Control ; Schistosomiasis ; epidemiology ; prevention & control ; Snails ; Soil

OBJECTIVETo evaluate the efficacy and safty of the humanized anti-epidermal factor receptor monoclonal antibody h-R3 in combination with radiotherapy for locoregionally advanced nasopharyngeal carcinoma.

METHODSTotally, 137 patients from 7 medical center around China were randomly divided into combined therapy group or control group. There was no difference in Karnofsky performance score between two groups. All patients in both groups received radical conventionally fractionated radiotherapy to the total dose of D(T) 70-76 Gy. For the combined therapy group, h-R3 was added at a dose of 100 mg i.v. weekly for 8 weeks started at the beginning of radiotherapy.

RESULTSOf the 137 eligilbe patients, 70 were in the combined therapy group treated by h-R3 plus radiotherapy and 67 in the control group by radiotherapy alone. The intent-to-treat (ITT) population consisted of 130 patients, while the per-protocol (PP) population was composed of 126 patients. The efficacy was assessed respectively at three point of time: the end of treatment, the 5th- and 17th-week after treatment. The complete response (CR) of the combined therapy group was significantly higher than that of the control group in both ITT and PP (ITT: 65.63%, 87.50%, 90.63% versus 27.27%, 42.42%, 51.52%; PP: 67.21%, 90.16%, 93.44% versus 27.69%, 43.08%, 52.31%; P < 0.05, respectively). The most common h-R3-related adverse reactions were fever (4.3%), hypotension (2.9%), nausea (1.4%), dizziness (2.9%) and rash (1.4%), which could be reversible if treated properly. Radiotherapy combined with 100 mg h-R3 i. v. weekly was tolerable and did not aggravate the side effects of radiation. The quality of life in the combined therapy group was comparable to that in the control group.

CONCLUSIONThis phase 1 multicenter clinical trial shows that h-R3 in combination with radiotherapy is effective and well-tolerated for the treatment of locoregionally advanced nasopharyngeal carcinoma.

Adult ; Aged ; Antibodies, Monoclonal ; adverse effects ; therapeutic use ; Carcinoma, Squamous Cell ; pathology ; therapy ; Combined Modality Therapy ; Female ; Fever ; etiology ; Humans ; Hypotension ; etiology ; Male ; Middle Aged ; Nasopharyngeal Neoplasms ; pathology ; therapy ; Neoplasm Staging ; Quality of Life ; Radiotherapy ; adverse effects ; methods ; Receptor, Epidermal Growth Factor ; immunology ; Remission Induction

Using the amino acids 1-147 of the yeast transcriptional activator GAL4 as the DNA-binding domain and four tandem repeats of the 12-aa peptide (DALDDFDLDMLG) of the herpesvirus as the activation domain, an artificial transcription factor, GVP4,was constructed via the linkage of the nuclear localization signal sequence of SV40. And then, GVP4 was cloned into expression vector pcDNA3 . 1/Hygro ( + ) . Various amounts of targeting sites of artificial transcription factor were linked to the upstream of promoter CMV in exogenous gene expression vector pcDNA3.1 ( + ) that separately harbored EGFP cDNA and t-PA cDNA.The CHO cells were then co-transfected with GVP4 expression vector and EGFP or t-PA expression vector. The effect of GVP4 on exogenous gene expression was evaluated by measuring the fluorescence intensity of EGFP in CHO cells and the concentration of t-PA in the supernatant. GVP4 showed positive effect on the enhancement of exogenous gene expression in CHO cells integrated with targeting sites of artificial transcription factor. And, CHO cells integrated with 10 targeting sites of GVP4 was more favorable to foreign gene expression, which resulted in 2-3-fold increase in both EGFP and t-PA expressions. These results indicated that artificial transcription factor is potent in the enhancement of exogenous gene expression in mammalian cells.
Amino Acid Sequence ; Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Flow Cytometry ; Gene Expression Regulation ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; metabolism ; Tissue Plasminogen Activator ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transcriptional Activation ; Transfection

By using the cell density, cell viability, size distribution of cell aggregates,specific consumption rate of glucose (q_ glc ), specific production rate of lactate (q_ lac ), lactate transform rate (Y_ lac/glc ) and amino acids utilization as the evaluation indexes, the growth and metabolism of HEK293 cells under carrier-free immobilization culture mode were examined and compared with those of HEK293 cells cultured in static tissue flasks. It was found that HEK293 cells grown as suspended cell aggregates in spinner flasks maintained the basic growth and metabolism characteristics of HEK293 cells in stationary anchored culture, and HEK293 cells under carrier-free immobilization culture mode as suspended aggregates in stirred bioreactor facilitate perfusion performance and increase unit productivity. Cultivation of HEK293 cells in carrier-free immobilization culture mode has potential for further improving mammalian cells culture technique.

Based on the different permeability of DNA-intercalant dyes YO-PRO-1(YP) and propidium iodide (PI) to the membrane of viable, apoptotic and necrotic cells, cell samples were stained with 4?mol/L YP and 4?g/ml PI for 10 min, and the fluorescence intensity of both YP and PI were measured by fluorometer at Ex/Em wavelength of 485/538nm and 530/590nm, respectively. The correlation between YP fluorescence intensity and the apoptotic cell number was confirmed by fluorescence microscope and linear regression(r=0.999,P