MicroRNA-497 suppress osteosarcoma by targeting MAPK/Erk pathway.

BACKGROUND: The aim of this study was to study the mechanism of miRNA-497 in the apoptosis of osteosarcoma cells. METHODS: MG-63 cells were divided into the three groups: NC, BL and miRNA groups, NC group were treated with nothing; BL group were transfected with blank vector; miRNA group were transfected with miRNA-497. Cell proliferation rate was detected by MTT method; Apoptosis rate was detected by flow cytometry and measuring the gene and protein expression of MAPK, Erk and P 21 by RT-PCR and Western blot. RESULTS: The cell proliferation rate of miRNA group was significantly lower compared to NC group and BL group (p < 0.05); while the apoptosis rate of miRNA group (32.17 ± 3.23 %) was significantly higher than that of NC group  (8.40 ± 1.78 %) and BL group (8.83 ± 0.99 %) (p < 0.05, respectively). Regarding the gene expression detection, we found that gene and protein expressions of MAPK, Erk and P21 of miRNA group were significantly different compared to NC and BL groups (p < 0.05, respectively). CONCLUSION: MiR-497 can activate P21 expression by inhibiting the expression of MAPK/Erk signaling pathway, thus promoting the apoptosis of osteosarcoma cells (Fig. 5, Ref. 18).

Isolation and partial characterization of novel genes encoding acidic cellulases from metagenomes of buffalo rumens.

AIMS: To clone and characterize genes encoding novel cellulases from metagenomes of buffalo rumens. METHODS AND RESULTS: A ruminal metagenomic library was constructed and functionally screened for cellulase activities and 61 independent clones expressing cellulase activities were isolated. Subcloning and sequencing of 13 positive clones expressing endoglucanase and MUCase activities identified 14 cellulase genes. Two clones carried two gene clusters that may be involved in the degradation of polysaccharide nutrients. Thirteen recombinant cellulases were partially characterized. They showed diverse optimal pH from 4 to 7. Seven cellulases were most active under acidic conditions with optimal pH of 5.5 or lower. Furthermore, one novel cellulase gene, C67-1, was overexpressed in Escherichia coli, and the purified recombinant enzyme showed optimal activity at pH 4.5 and stability in a broad pH range from pH 3.5 to 10.5. Its enzyme activity was stimulated by dl-dithiothreitol. CONCLUSIONS: The cellulases cloned in this work may play important roles in the degradation of celluloses in the variable and low pH environment in buffalo rumen. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided evidence for the diversity and function of cellulases in the rumen. The cloned cellulases may at one point of time offer potential industrial applications.

Access of a membrane protein to secretory granules is facilitated by phosphorylation.

Peptidylglycine alpha-amidating monooxygenase (PAM), an integral membrane protein essential for the biosynthesis of amidated peptides, was used to assess the role of cytosolic acidic clusters in trafficking to regulated secretory granules. Casein kinase II phosphorylates Ser(949) and Thr(946) of PAM, generating a short, cytosolic acidic cluster. P-CIP2, a protein kinase identified by its ability to interact with several juxtamembrane determinants in the PAM cytosolic domain, also phosphorylates Ser(949). Antibody specific for phospho-Ser(949)-PAM-CD demonstrates that a small fraction of the PAM-1 localized to the perinuclear region bears this modification. Pituitary cell lines expressing PAM-1 mutants that mimic (TS/DD) or prevent (TS/AA) phosphorylation at these sites were studied. PAM-1 TS/AA yields a lumenal monooxygenase domain that enters secretory granules inefficiently and is rapidly degraded. In contrast, PAM-1 TS/DD is routed to regulated secretory granules more efficiently than wild-type PAM-1 and monooxygenase release is more responsive to secretagogue. Furthermore, this acidic cluster affects exit of internalized PAM-antibody complexes from late endosomes; internalized PAM-1 TS/DD accumulates in a late endocytic compartment instead of the trans-Golgi network. The increased ability of solubilized PAM-1 TS/DD to aggregate at neutral pH may play an important role in its altered trafficking.

Age estimation on the female sternum by quantification theory I and stepwise regression analysis.

One hundred and nine sternums from Chinese females aged 18-50 years were examined in this study. Six morphological characteristics and their changing degree in the female sternum were observed and scored. The data were statistically processed by quantification theory I and stepwise regression analysis on a computer and the following regression equation for age estimation of the female sternum was calculated: y = 19.28 + 1.83x1 + 1.66x2 + 3.02x3 + 1.57x4 + 3.02x5 + 7.75x6 + 1.25x7 + 3.45x8 + 4.88x9 + 0.82x10 + 2.76x11 + 2.48x12 + 7.84x13 + 1.26x14 + 3.80x15 (the correlation coefficient R = 0.9774, the standard deviation S = 2.20, F > 0.01). For convenience, the changing degree of the morphological characters and the equation were also converted into two tables. This method of age estimation on the female sternum is simple and accurate and is of importance to forensic medicine and anthropology.

An epidemic of encephalitis and meningoencephalitis in children caused by echovirus type 30 in Shanghai.

An outbreak of viral central nervous system infection occurred from May to September, 1991 in Shanghai, China. Totally 376 cases were admitted into our hospital, 54% with encephalitis and 46% with meningoencephalitis. Echovirus type 30 was isolated from CSF and stools of the patients. Only 3 of the patients were under 1 year of age. CSF examination revealed the cell count from 0-1600 x 10(6)/L. Interestingly, 9 had CSF PMNs over 90% and 13 had low sugar levels. EKG was randomly done in 20 patients and 15 demonstrated myocarditis. The outcome was uneventful in all except 1 who had psychological problem at the time of discharge.