Problems and Their Solutions of PBL Teaching in Medical Microbiology / 微生物学通报

PBL(Problem-Based Learning, PBL) is a problem-oriented and effective supplementary teaching method. PBL is giving a great help to improve self-learning, communication and cooperation, thinking and problems solving abilities for the students. In the process of PBL teaching, attention should be paid to two important items. One item is the role transfer for the teacher. Teacher is only a guider in PBL teaching, teacher should avoid excessive interfere of the process for keeping the passion and enthusiasm of the students. Meanwhile, students should always be realized that they are the main part in PBL teaching, they should not depend on their teacher too much. Another important item is how to find and solve the frequently encountered problems, in order to avoid students wandering from the subject, and lead them toward the main goal to get effective teaching and learning.

Prokaryotic Expression and Acetylation Assays of Histone Acetyltransferase PCAF / 中国生物工程杂志

P300/CBP-associated factor(PCAF),an important member of histone acetyltransferase family(HATs) within eukaryotic cells,is capable of inducing the acetylation of histone,promoting the transcription of specific genes and involving in many biological effects.In the present study,full-length cDNA of PCAF was inserted into plasmid pGEX-5x-1,then the soluble protein GST-PCAF was expressed in E.coli BL21(DE3) after the optimization of inducing conditions.The recombinant protein was further purified with affinity chromatography and tested the activity by in vitro acetylation assays.High efficient PCAF protein produced by this method could serve for the study on the role of PCAF in gene regulation and the interaction between PCAF and other proteins.

Comparison between two methods for staining DNA of apoptotic spermatozoa / 中华男科学杂志

<p><b>OBJECTIVE</b>To compare two fluorochrome staining methods for the assessment of sperm quality.</p><p><b>METHODS</b>Washed sperm cells were incubated in 0, 0.15, or 15 micromol/L camptothecin (CAM), or 0.37 or 3.7 mmol/L genistein (GEN) at 37 degrees C for 4 hours. The sperm cells were analyzed for cycle-independent apoptosis and necrosis by single-stain compared with dual-stain fluorescence microscopy to contrast the relative effectiveness of these two approaches.</p><p><b>RESULTS</b>The single-stain procedure could not detect the sperm viability differences. In contrast, the dual-stain procedure identified a dosage-dependent decrease in the viability and increased necrozoospermia after topoisomerase inhibitor CAM and GEN treatments. Apoptosis was 2-fold higher with topoisomerase inhibitor treatment.</p><p><b>CONCLUSION</b>The two topoisomerase inhibitors were associated with increased apoptosis and dosage-dependent necrosis. The data suggested that the dual-stain combination Hoechst 33342/PI was more sensitive than the single Hoechst 33342 stain analysis and permitted quantitative analysis of the apoptosis and necrosis in sperm.</p>

The correlations between plasma TNF-alpha, NO, NOS levels and brain lateralization in mice / 生理学报

The brain modulates the immune system in an asymmetrical way, as shown by the association between paw preference and immune response in the mice. The purpose of the present work was to study the relationship between plasma tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and nitric oxide synthase (NOS) and brain lateralization. In the study, paw preference test was used to select right-pawed, left-pawed and ambidextrous mice. Mice were classified as the right-pawed if the right paw entry (RPE) score was equal to or greater than 30 (30-50), as the left-pawed if the score was equal to or less than 20 (0-20), and as the ambidextrous if the score was between 21 and 29. One week after the paw preference testing, the animals were injected intraperitoneally with either sterilized 0.9% saline or lipopolysaccharide (LPS) (5 microg/0.5 ml NS) and were killed 2 h later. Plasma was collected from each mouse. The level of plasma TNF-alpha was measured with ELISA kits provided by ENDOGEN. NO and NOS levels of plasma were detected with kits from Juli Biotechnology Company. The results showed that (1) in the normal mice, ambidextrous mice had higher NO levels compared with left-pawed mice (P<0.05). After the injection of LPS, plasma level of TNF-alpha was lower in left-pawed mice compared with those of the right-pawed and ambidextrous mice; plasma level of NO was higher in ambidextrous mice compared with those of the right- (P<0.01) and left-pawed (P<0.05) ones, and there was no significant difference in the plasma levels of NOS among ambidextrous, right- and left-pawed mice. (2) Immune parameters were correlated with the RPE scores. The shape of the curve describing this relation was similar to a parabola. In general, the levels of TNF-alpha, NO, NOS rose along with the increase of RPE if the scores were in the score range of left-pawed mice.After that, they reached a peak if the scores were in the score range of ambidextrous mice. Then they declined along with the increase of RPE if the scores were in the score range of right-pawed mice. In conclusion, plasma levels of TNF-alpha, NO and NOS were associated with brain lateralization, suggesting that the activities of Mo/Mphi were influenced by brain lateralization, and that the immune parameters were correlated with the RPE scores.

The Application of CBS in the Teaching of Medical Microbiology / 微生物学通报

CBS(Case Based Study)is a new teaching method,which is based on the case given.It requires students to answer questions according to the case. In the teaching,the students who are divided into groups,seek for resolvent by themselves. They should combine the information provided in the case,find the key answer and the relationship.The students gain the knowledge by reviewing and studying in the textbook,then analyse and solve questions with them. The application of CBS could make knowledge more relatively and systematic, moreover,it also make study more actively and initiatively.