Isolation, identification and genetic analysis of a murine norovirus strain / 病毒学报

Murine norovirus (MNV) was first discovered in mice in 2003. MNV is a member of the genus Norovirus in the family Caliciviridae. It is one of the most important and prevalent pathogens of laboratory mice, and almost all mouse strains are susceptible to MNV infection. In this study, a MNV strain was isolated from the cecal contents of infected mice and identified by the cytopathic effect (CPE) assay, virus plaque assay, 50% tissue culture infectious dose (TCID50) assay, electron microscopy, indirect immunofluorescence assay (IFA) and nucleotide sequencing. On infection, the RAW264.7 cell line showed obvious cytopathic effects within 24 to 48 hours post-inoculation, as infected cells became rounded, bright and shrunken, with ultimate disintegration of the cell sheet. After the isolation of the MNV virus, the virus was plaque-purified in RAW264.7 cells. The TCID50 of the virus was 10(5.25/0.1 mL. Electron microscopic observations of the purified virus showed the presence of spherical and non-enveloped viral particles that were 30 to 35 nm in diameter. According to the identification results, the isolate was named as MNV Guangzhou/K162/09/CHN. Thereafter, five overlapping gene fragments that covered the entire open reading frame (ORF) were amplified by RT-PCR, and the 3'-untranslated region (UTR) and 5'-UTR were amplified using the 3'-rapid amplification of cDNA ends (RACE) and the 5'-RACE method, respectively. Each of the gene fragments were cloned and sequenced, and whole genome sequences of the strain were obtained by assembling the cDNA fragment sequences. The results showed that the length of the complete genome was 7 380 nucleotides (GenBank accession number: HQ317203). The comparison of nucleotide and deduced amino acid sequences of the isolate was performed against other MNV strains in the GenBank database. A phylogenetic tree based on VP1 nucleotide sequences was constructed using MEGA5.0 software. The homology of nucleotides between the MNV Guangzhou/K162/09/CHN strain and other MNV isolates ranged from 87.4% to 89.7%. Phylogenetic analysis showed that there was a close genetic relationship between the Guangzhou/K162/09/CHN strain and MNV strains isolated from Japan (S7-P2 and S7-PP3 isolates), Korea (K4 isolate), and Germany (Berlin/04/06/DE and Berlin/05/06/DE isolates). This is the first report of the isolation and identification of MNV in China, and the first report of the genetic analysis of its complete genome.

Model index observations in SIVmac251-infected rhesus macaques / 病毒学报

In this study, five rhesus macaques were inoculated intravenously with SIVmac251 to establish a model of simian autoimmune deficiency syndrome (SAIDS). Peripheral blood samples were collected at different time points to monitor changes in the total T cell number and T lymphocyte subset. Plasma viral loads, cytokine expression levels and anti-SIV antibody levels were also assayed to acquire certain basic indexes to evaluate disease progression in the rhesus macaque SAIDS model. During the acute stage of infection, plasma viral loads reached a peak at week 1 post-inoculation and lasted for approximately 3 to 44 weeks. The CD3+ CD4+ T lymphocyte count in peripheral blood also transitorily decreased. During the same period, the level of interferon-gamma show an increasing trend, whereas IL-12 levels decreased; IL-2, IL-4, IL-10 and TNF-alpha were maintained at normal levels or could not be detected. During the asymptomatic and ARC phases, plasma viral loads persisted above 10(4) RNA copies/mL and either increased or declined during the later stages of disease; CD3+ CD4+ counts showed a steadily declining trend and the ratio of CD4 to CD8 decreased during late-stage disease. Moreover, antibodies against viral proteins were detected in the plasma and showed a significant increasing trend, while there were no apparently changes in the levels of IFN-gamma, IL-12, IL-2, IL-4, IL-10 and TNF-alpha. In conclusion, the characteristics of the SIV animal models in our study are similar to those of patients with AIDS. Therefore, the rhesus macaque SIVmac251 infection models can be applied for further studies into AIDS.

Expression of quorum-sensing related genes during Enterococcus faecalis biofilm formation / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the expression of the quorum-sensing related genes during Enterococcus faecalis(Ef) biofilm formation.</p><p><b>METHODS</b>Ef biofilms model was established in vitro and film formation process was observed by confocal laser scanning microscope at 6, 12, 24 and 48 hours respectively.Quantification of biofilms was achieved by staining with crystal violet.Real-time fluorescence quantitative PCR method was used to detect the expression of fsrB, gelE and sprE genes in the process of Ef biofilm formation.</p><p><b>RESULTS</b>A lot of live and dead bacteria unevenly distributed in Ef biofilm. The quantity of biofilms increased with time within 24 hours and was 0 h:0.00 ± 0.00, 6 h:1.09 ± 0.13, 12 h:2.10 ± 0.79, 24 h:3.30 ± 0.13, which was significantly different among the 4 time period(P < 0.05). The quantity of biofilm at 48 h(3.51 ± 0.01) increased slightly compared with 24 h(3.30 ± 0.13) , but did not show significant difference.Quantitative real-time PCR showed that the expression of quorum-sensing related fsrB increased with time within 24 hours and was 0 h:9.98 ± 0.46, 6 h:23.45 ± 1.13, 12 h:47.30 ± 2.49, 24 h: 331.30 ± 2.18, which was significantly different among the 4 time period(P < 0.05). The expression of gelE was 0 h: 6.54 ± 0.73, 6 h: 14.26 ± 1.24, 12 h: 37.47 ± 2.35, 24 h:264.80 ± 5.10(P < 0.05). The expression of sprE was 0 h: 7.72 ± 0.74, 6 h: 21.15 ± 0.96, 12 h:49.87 ± 3.18, 24 h:441.89 ± 7.74, which was significantly different among the 4 time period(P < 0.05).</p><p><b>CONCLUSIONS</b>The fsrB, gelE and sprE genes are closely related to the biofilm formation in Ef.</p>

Health status and affecting factors of late-preterm infants / 中华儿科杂志

<p><b>OBJECTIVE</b>To study the birth rate, mortality, complications, related factors of preterm infants at Beijing Haidian Maternity and Children's Hospital in 2007, so as to establish the foundations for a more systematic and effective program for clinical treatments.</p><p><b>METHODS</b>Data of all the neonates born at Beijing Haidian Maternity and Children's Hospital during the period from January 1, 2007 to December 31, 2007 were recorded for statistical analysis. All near-term infants of 35 - 37 weeks of gestational age were taken into observation group. Within 24 hours after birth, blood routine examination, urine and stool routine examination, blood gas analysis and electrolytes, blood glucose monitoring (at 1st, 3rd, 6th, 12th, and 24th hours), chest radiography examination, skull and heart color Doppler ultrasonographic examination were conducted. Full-term infants who were born on the first day of every month were randomly selected as a comparison group (totally 350 cases) for statistical analysis. Complications of the two groups were recorded in detail. Factors such as the ages of parturients, maternal infections, pregnancy-induced hypertension, diabetes, anaemia, premature rupture of membranes, abnormal aminotic fluid, abnormal umbilical cord, abnormal placenta, and twin were analyzed and compared.</p><p><b>RESULTS</b>Of the 12,286 infants born during the study period, 333 were late-preterm infants; the birth rate of late-preterm infants was 2.71%. Among the complications in late-preterm infants, the hyperbilirubinemia topped at 33.6%, followed by respiratory distress (16.8%), hypoglycemia (9.0%), intracranial hemorrhage (8.1%), anemia or erythrocytosis (5.7%), and digestive system disease (5.4%). Late-preterm infants have higher rate of the hyperbilirubinemia, respiratory distress, hypoglycemia, anemia or erythrocytosis and digestive system disease (P < 0.05). The length of hospital stay of late-preterm infants, which is 5.1 d +/- 3.90 d, was significantly longer than those of full-term infants which was 3.2 d +/- 1.61 d (P < 0.05).</p><p><b>CONCLUSION</b>The proportion of late-preterm infants was 2.71% of all live born infants at Beijing Haidian Maternity and Children's Hospital from January 1, 2007 to December 31, 2007. The occurrence rate of complications and mortality rate were higher than those of full-term infants. Late-preterm infants also have longer hospital stay. Hyperbilirubinemia is a common complication for late-preterm infants. Pregnancy-induced hypertension, anemia, premature rupture of membranes and twins are the major causes of higher morbidity and mortality of late-preterm infants. Pediatricians should pay much more attention to late-preterm infants, and should accept them for further observation and treatments.</p>

Observation on Rhesus monkeys infected second time with H5N1 avian influenza virus / 病毒学报

Rhesus monkeys with high specific H5N1 antibody were inoculated the second time with H5N1 virus, the result of the second time H5N1 inoculation and the effect of first time H5N1 inoculation on second inoculation was evaluated. Monkeys of NO. 3, NO. 4, NO. 5 were inoculated with H5N1 allantoic fluid and NO. 6 with noninfectious allantoic fluid by intratracheal thyrocricoid puncture. Three months later, NO. 4, NO. 5, NO. 6 monkeys were infected with 7 ml TCID50 10(4.875) H5N1 allantoic fluid and NO. 3 monkey with 7 ml noninfectious allantoic fluid at the same time by the same method. Clinical symptoms were recorded and antibody response was detected by ELISA. NO. 3, NO. 4, NO. 6 monkeys were killed after 72 h post infection and NO. 5 monkey was killed after 7 days post infection. Pathologic changes of the infected monkeys' lung were examined by HE staining,immunohistochemistry and the virus in lung was detected by RT-PCR. Results showed that NO. 3, NO. 4, NO. 5 monkeys still retained high level of specific antibody, H5N1 virus only could be detected in NO. 6 monkey's lung by immunohistochemistry and RT-PCR ,and the lung of NO. 6 monkey injured worst . It can be concluded that Rhesus monkeys inoculated with H5N1 avian influenza A virus at the first time could retain a high level of specific antibody in 90 days and the clinical symptom had almost recovered, the ability of Rhesus monkeys to resist second infection of H5N1 virus was enhanced notably at that moment.

GROWTH AND MORPHOLOGY OF LEPTOSPIRILLUM FERROOXIDANS ON SOLID MEDIUM / 微生物学通报

Single clones of Leptospirillum ferrooxidans were obtained on bilayer solid medium plate by incorporating Het-erotroph Acidiphilium SJH into the underlayer broth medium. The morphologies of the bacteria were investigated using electronic microscope.

Effect of Strengthening the Spleen and Tonifying the Kidney on the Function and Apoptosis of Kidney in Rats after Exhaustive Exercise / 中医杂志

Objective To study the effect and mechanism of strengthening the spleen and tonifying the kidney on the function and apoptosis of kidney in rats.Methods The 42 male SD rats were randomly divided into quiet control group,exhausted exercise group and strengthening the spleen and tonifying the kidney group.Twenty four hours after exhaustive exercise,the concentrations of blood urea nitrogen(BUN),serum creatinine and urinary protein were determined.The apoptosis in kidneys of rats was detected by TUNEL.The structure of kidney was observed in the HE stain.Results Comparing with the exhausted exercise group,the concen- trations of BUN,serum creatinine and apoptotic index were lower significantly(P

Study and Application of Bacterial Mercury-resistance Mechanism and Evolution / 微生物学通报

There exist a number of mercury-resistant bacterial in environment, Mer operon is involved in the resistant mechanism, MerRTPA of Mer operon encodes the proteins related to the regulation, transport and reduction of mercury ion, respectively. The toxic mercury ion is transported by MerTP from medium to cytoplasmic mercuric reductase, MerA, and deoxidized to non-toxic and volatile element mercury, Hg(0). Bacterial mercury-resistant system originated from ancient times, and evolved into the Mer operon with diversity by gene integration and insertion. Mercury-resistant bacteria highly specifically absorb mercury ion, and can be used in recovering the mercury-polluted environment as well as the genetic selective marker.