In vitro antibacterial and osteogenic properties of plasma sprayed silver-containing hydroxyapatite coating

The objective of the present investigation was to characterize the antibacterial and osteogenic properties of plasma sprayed silver-containing hydroxyapatite （HA/Ag） coating in vitro. HA/Ag coating was deposited via vacuum plasma spraying. The concentration of silver ions released from HA/Ag coating, the efficacy of the HA/Ag coating against bacterial biofilm development, the effect of the HA/Ag coating on early adhesion and ossification of osteoblast cells in vitro was measured. The silver ion concentration released from the HA/Ag coating was between the minimum inhibitory concentration to bacteria and the cytotoxic concentration. Bacterial biofilm inhibition studies indicated an antibacterial activity on the HA/Ag coating surface when compared with hydroxyapatite （HA） coating alone. Moreover, it was demonstrated that osteoblast cell adhesion and mineralization occurred on the HA/Ag coating surface during the testing period. We conclude that the vacuum plasma sprayed HA/Ag coating possesses good antibacterial capability and osteogenic properties in vitro and represents a promising candidate for coating orthopedic implants.     

A BAC clone of MDV strain GX0101 with REV-LTR integration retained its pathogenicity

The complete genome of Marek＇s disease virus （MDV） strain GX0101, which was integrated with the LTR sequences of REV, was cloned in Escherichia coli as a bacterial artificial chromosome （BAC）. BAC vector sequences were introduced into the US2 locus of the MDV genome by homologous recombination. The viral DNA containing the BAC vector was used to transform Escherichia coli strain of DH10B. Then the recombinant virus was successfully rescued by transfection of the recombinant BAC DNA into primary chicken embryo fibroblast （CEF）. This BAC viral clone was named bac-GX0101. When the reconstituted virus was inoculated into 1-day-old birds, visceral tumors could be detected as early as 62 d post infection. There was no difference in growth ability and pathogenicity to birds between the BAC derived virus and its parental virus. The BAC derived virus maintained its oncogenicity and immunosuppressive effects. In conclusion, the complete genome of GX0101 strain was successfully cloned into BAC and the infectious clone was rescued. With the powerful BAC manipulation system, the infectious clone will provide a useful tool for further understanding the functional roles of the inserted REV-LTR sequence in the GX0101 strain of MDV,     

Immune response in cattle inoculated with the recombinant complete polyprotein of foot-and-mouth disease virus from Bombyx mori larvae

The intact open reading frame (ORF) of foot-and-mouth disease virus (FMDV) Asia I/XJ strain was am- plified by RT-PCR and inserted into the transfer vector pVL1393 to generate plasmid pVL-ORF. Bm-N cells were transfected with pVL-ORF and linearized Bm-BacPAK6 DNA, and the recombinant silkworm baculovirus Bm-ORF containing the full ORF of FMDV was obtained. The results of indirect im- munofluorescence assay (IFA) showed that Bm-ORF could be expressed efficiently in Bm-N cell. After inoculating the early 5th instar larvae of silkworm, the polyprotein of FMDV could be detected by sandwich ELISA and empty capsid-like particles could be observed under the electron microscope. Expression products from silkworm were used as the antigen to immunize the cattle. The specific an- tibody was induced in all vaccinated animals. The immunized cattle were challenged with the virulent FMDV Asia I/XJ strain, two of the four cattle were completely protected and clinical symptoms were alleviated and delayed in the others. The results suggest that this strategy might be used to develop the new subunit FMDV vaccine.     

Visualization of Gene Mutation Complicated Pattern of Hepatitis B Virus Based on Cellular Automata

Hepatitis B virus shows instantaneous and high rate mutations in biological experiments, some sorts of which affect the efficiency of virus replication greatly through enhancing or depressing the viral replication, while others have no influence at all. Taking advantage of prominent features of cellular automata, we simulate the effect of hepatitis B virus gene mutation on its replication efficiency. The computer simulation results demonstrate the feasibility of our novel model by comparing with the results of biological experiments.     

Construction and<Emphasis Type="Italic">in vitro</Emphasis> study of an E1B-defective adenovirus

An E1B-defective adenovirus named rl/Ad was constructed by homologous recombination.The construction,selection and propagation of recombinant virus was done in the human embryonic kidney 293 cells (HEK293).The in vitro study demonstrated that the recombinant virus has the ability to replicate in and lyse some p53-deficient human tumor cells such as the human glioblastoma tumor cells (U251) and human bladder tumer cells (EJ) but not in the normal cells with functional p53 such as the human fibroblast cells (MRC-5).Also,based on the cytopathic effect (CPE),it was demonstrated that the U251 cells were more sensitive to the infection of rl/Ad than that of EJ cells under identical conditions.In this paper,it was found that rl/Ad could be very useful in studying the in vitro selective replication of E1B-defective adenovirus.This may help to determine the safety of using any E1B-defective adenoviruses in cancer gene therapy.     

Effect of leptin on oocyte maturation and subsequent pregnancy rate of cloned embryos reconstructed by somatic cell nuclear transfer in pigs

Cloning pigs by somatic cell nuclear transfer （SCNT） has wide applications in basic research, human medicine and agricultural production. To improve cloning efficiency, the effect of two basic maturation media, NCSU-23 and TCM199, was compared, and TCM199 was selected for the following experiments with leptin. We systematically studied the effects of leptin supplementation on oocytes in vitro maturation （IVM）, in vitro development of parthenogenetically activated （PA） and SCNT embryos and in vivo development of SCNT embryos after embryo transfer （ET）. The results showed that supplementation of 100 or 200 ng/ml leptin into the maturation medium did not greatly affect nuclear maturation of oocytes, or cleavage rates of PA and SCNT （P 〉 0.05）. Blastocyst rates of PA and SCNT embryos were significantly improved when 100 or 200 ng/ml leptin was added to maturation medium, and the number of cells in PA blastocysts was also improved （P 〈 0.05）. The number of cells in blastocyst of SCNT was improved, when 100 ng/ml leptin was added （P 〈 0.05）. Furthermore, supplementation of 100 or 200 ng/ml leptin to the IVM medium may improve pregnancy rate and the delivery rate inpig cloning.     

The bio-barite in witherite deposits from Southern Qinling and its significance

Being stratiform or stratoid, the Huangboshuwan witherite deposit at Zhiyang and the Wenyuhe witherite-barite deposit at Zhushan occur in the lower Lower Cambrian siliceous rocks and the orebodies are remarkably controlled by lithological character and petrography. Carbon and oxygen isotopic studies of witherite, barytocalcite and calcite have shown that the carbon, involved in the formation of these minerals, was derived largely from organic carbon resultant from degradation, polycondensation and dehydroxylation of bio-organic matter in sediments at the early stage of diagenesis. Extensive occurrence of bio-barite strongly evidenced that Ba2+ was concentrated and settled down in the form of bio-barite on the seafloor as a result of biological processes, thereafter forming the initially enriched orebodies of barium deposits. The witherite was metasomatic products of bio-barite under the action of sulfate-reducing bacteria and organic and inorganic reduction.     

In fl uence of HEPES buffer on the local pH and formation of surface layer during in vitro degradation tests of magnesium in DMEM

The human body is a buffered environment where p H is effectively maintained. HEPES is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPES on the degradation behavior of magnesium in the DMEM pseudo-physiological solution has not yet been determined. The research aimed at elucidating the degradation mechanisms of magnesium in DMEM with and without HEPES. The morphologies and compositions of surface layers formed during in vitro degradation tests for 15–3600 s were characterized. The effect of HEPES on the electrochemical behavior and corrosion tendency was determined by performing electrochemical tests. HEPES indeed retained the local p H, leading to intense intergranular/interparticle corrosion of magnesium made from powder and an increased degradation rate. This was attributed to an interconnected network of cracks formed at the original powder particle boundaries and grain boundaries in the surface layer, which provided pathways for the corrosive medium to interact continuously with the internal surfaces and promoted further dissolution. Surface analysis revealed significantly reduced amounts of precipitated calcium phosphates due to the buffering activity of HEPES so that magnesium became less well protected in the buffered environment.     

Soluble Jagged 1/Fc chimera protein induces the differentiation and maturation of bone marrow-derived dendritic cells

A soluble Jagged 1/Fc chimera protein （Jagged 1/Fc） was directly used to induce differentiation and maturation of bone marrow-derived dendritic cells （DCs） in mice in vitro. A model of inducing and amplifying DCs in vitrowas established. The effect of Jagged 1/Fc on morphology of DCs induced by both rmGM-CSF and rmlL-4 was observed under a confocal microscope. A fluorescein-labeled monoclonal antibody staining combined with flow cytometry was applied to detect the effect of Jagged 1/Fc on the expression of CD11c, MHC-Ⅱ, CD86, CD80 and CD40 molecules on the surface of DCs. The results showed that Jagged 1/Fc did not affect the morphological properties of DC differentiation induced by both rmGM-CSF and rmlL-4. But it could promote the differentiation and maturation of DCs induced by both. The effect of it was strikingly different in the expression profile of co-stimulating molecules and the morphologic properties of DCs from lipopolysaccharide （LPS）. The levels of MHC-Ⅱ and CD40 molecule expression on the surface of DCs stimulated by Jagged 1/Fc were significantly lower than those stimulated by LPS, and the level of CD80 expression on the surface of DCs induced by Jagged 1/Fc was near to that induced by LPS. Jagged 1/Fc had no influence on the expression of CD86 molecule on the surface of DCs. Jagged 1/Fc when used alone could not maintain the growth, differentiation and maturation of DCs. All the findings indicate that Jagged 1/Fc influences the differentiation and maturation of DCs, which is not markedly similar to LPS, providing important evidence for its development and application as a novel immunosuppressant.     

Infective viruses produced from full-length complementary DNA of swine vesicular disease viruses HK/70 strain

Swine vesicular disease (SVD) is a highly conta- gious viral disease of pigs. Symptoms are clinically indistinguishable from those caused by other vesiculardisease viruses, such as foot and mouth disease (FMD virus, vesicular stomatitis (VS) virus and ves…     

Construction and identification of reverse genetics system of Dengue type 2 virus isolated in China

Dengue (DEN) viruses, mosquito-borne pathogens of the Flavivirus genus, Flaviviridae family, are envel- oped RNA viruses that contain a single-stranded, posi- tive-sense, capped RNA genome of approximately 11 kb. Single polypeptide is co-translationlly pr…     

Rescued virus from infectious cDNA clone of rabbit hemorrhagic disease virus is adapted to RK13 cells line

RHDV is an extremely pathogenic virus. The mor-tality rate of infected rabbits is almost 99%. The dis-ease caused by RHDV is also called “rabbit plague”, and it has been regarded as one of the most important infection diseases of rabbits. RHDV was desig…     

Sequencing and rescuing a highly virulent classical swine fever virus： Chinese strain cF114 from a full-length cDNA clone

Classical swine fever is an economically important, highly contagious disease of pigs caused by the classical swine fever virus (CSFV), as referred to as hog cholera virus. CSFV belongs to Pestivirus within the family of Flaviviridae. The virus contains a positivestranded RNA of approximately 12.3 kb in length[1]. The genome is composed of a 5′ non-coding region, a single large open reading frame (ORF) encoding the viral polyprotein with 3898 amino acid residues and a 3′ non-coding reg…     

Construction of cytopathic PK-15 cell model of classical swine fever virus

No cytopathic effect (CPE) can be observed on classical swine fever virus (CSFV) infected cell culture in vitro. This brings an obstacle to the researches on reciprocity between CSFV and host cells. Based on the construction of full-length genomic infectious cDNA clone of Chinese CSFV standard virulent Shimen strain, partial deletion is introduced into genomic cDNA to obtain a 7.5 kb subgenomic cDNA. A new subgenomic CSFV is derived from transfection with the subgenomic cDNA on PK-15 cells pre-infected by CSFV Shimen virus. Typical CPE induced by this subgenomic virus is observed on PK-15 cells. Coexistence of wildtype and subgenomic virus in cytopathic cell culture is demonstrated by RT-PCR detection in cytopathic cells. For conclusion, the construction of cytopathic cell model exploited a new way for researches on the molecular mechanism of CSFV pathogenesis.     

A molecular clone of HTLV-III with biological activity

Acquired immune deficiency syndrome (AIDS) is an epidemic immunosuppressive disease characteristically associated with a depletion of T lymphocytes of the helper/inducer phenotype. Numerous converging lines of research have implicated a human T-cell lymphotropic retrovirus, HTLV-III, in the pathogenesis of AIDS. Recently, several distinct forms of the HTLV-III genome were molecularly cloned in phage and extensively characterized. In the present study, a clone containing full-length HTLV-III proviral DNA was inserted into a plasmid and used to transfect cord blood T cells from normal newborn humans. We demonstrate that this molecular clone is infectious in vitro and causes marked cytopathic effects on T-cell cultures. This is the first direct evidence that the HTLV-III genome, rather than a minor component of the virus complex, is cytopathic for T cells. Using this biologically competent clone and mutants derived from it, it should now be possible to localize the subgenomic regions that contribute to the biological effects of HTLV-III.     

抗白粉病的小麦-黑麦1BL/1RS易位系99/2439的cDNA文库构建

用pGEMT-easy质粒载体构建了经白粉茵诱导0.5h、1.0h、12h、24h和48h的小麦-黑麦1BL/1RS易位系99/2439叶片cDNA文库1个.文库宿主茵为E. coliDH10B,诱导文库平均插入片段为1kb左右.     

广西猪瘟病毒的调查研究

１９８６～１９８９年，从广西５个地、市的１０个病猪场猪体中分离到１０个病毒。用猪瘟石门系标准强毒作对照，经病原性、抗原性及血清学试验，培养特性，血细胞吸附及病毒的形态结构观察，证明１０个毒株为猪瘟病毒。它们有共同的抗原性。它们之间的区别只是毒力的强弱不同。从临床症状、病理变化和病程方面看，９个为亚急性猪瘟毒株；一个为慢性或温和性猪瘟毒株。