On-site Determination of Element Concentrations in Marine Sediments and Comparative Study of Analytical Methods / 分析化学

Epsilon 3xenergy dispersive X-ray fluorescence spectrometer (EDXRF) was used to analyze the major and minor elements in marine sediments collected from the Indian Ocean on-site. Results obtained by EDXRF were compared with those by inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) in the laboratory A total of 24 elements in marine sediment samples,namely Al2O3,MgO,Fe2O3,Na2O,K2O,CaO,Mn,P,Ti,Ba,Sr,V,Zn, Zr, Co,Ni,Cu,Ga,Rb,Y,Nb,Mo,Nd,Pb and Th were measured,and a good agreement was found for these elements(R2>0.9),except for Al2O3,and Ga,Nb and Th with content lower than 30 μg/g. The mean relative deviations of EDXRF method were less than 10% for all of the above mentioned major elements, except for MgO in low concentration and P in high concentration. The mean relative deviations were less than 25% for all of the above mentioned trace elements,except for Sr(>700 μg/g),Mo(<20 μg/g) and Nb. In general, precision and accuracy of EDXRF method were good enough for detection of marine sediments. Taking into account all these facts, the EDXRF method proposed here was proved to be an effective tool for element determination in marine sediment on-site,and it would provide a new technical support to investigate the spatial distribution of mineral resources in marine geological survey.

Protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat

OBJECTIVE@#To study the protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat.@*METHODS@#A total of 84 Wistar rats were divided into 4 groups: 12 in Group A (control group), 24 in Group B (diabetic cataract group), 24 in Group C (therapeutic-dose of resveratrol group) and 24 in Group D (low-dose of resveratrol group). Rats in Group B-D were given with 60 mg/kg streptozotocin through intraperitoneal injection. Rats in Group C were given with 100 mg/kg resveratrol and rats in Group D were given with 20 mg/kg resveratrol. The caspase-3 expression levels and apoptosis ratios of LEC among each group were observed; the degrees of lens opacity in Group B-D after 12 weeks were compared.@*RESULTS@#There were significant differences in caspase-3 expression levels, apoptosis ratios of LEC among groups at 4 w, 8 w and 12 w (P<0.05). After 12 weeks, in Group B the degree of lens opacity was as follow: 0 (0.00%) in grade I, 3 (37.50%) in grade II, 2 (25.00%)in grade III, 2 (25.00%)grade IV, and 1 (12.50%) in grade V; in Group C: 2 (25.00%)in grade I, 4 (50.00%) in grade II, 2 (25.00%)in grade III, 0 (0.00%)grade IV, and 0 (0.00 %) in grade V; in Group D: 1 (12.50%)in grade I, 4 (50.00%) in grade II, 2 (25.00%) in grade III, 1 (12.50%) grade IV, and 0 (0.00%) in grade V. The difference among Group B-D was statistically significant (P<0.05).@*CONCLUSIONS@#Resveratrol has protective effect on lens epithelial cell apoptosis in diabetic cataract rat, and the effect is relative to its dose.

Protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat

Objective: To study the protective effect of resveratrol on lens epithelial cell apoptosis in diabetic cataract rat. Methods: A total of 84 Wistar rats were divided into 4 groups: 12 in Group A (control group), 24 in Group B (diabetic cataract group), 24 in Group C (therapeutic-dose of resveratrol group) and 24 in Group D (low-dose of resveratrol group). Rats in Group B-D were given with 60 mg/kg streptozotocin through intraperitoneal injection. Rats in Group C were given with 100 mg/kg resveratrol and rats in Group D were given with 20 mg/kg resveratrol. The caspase-3 expression levels and apoptosis ratios of LEC among each group were observed; the degrees of lens opacity in Group B-D after 12 weeks were compared. Results: There were significant differences in caspase-3 expression levels, apoptosis ratios of LEC among groups at 4 w, 8 w and 12 w (. P<0.05). After 12 weeks, in Group B the degree of lens opacity was as follow: 0 (0.00%) in grade I, 3 (37.50%) in grade II, 2 (25.00%)in grade III, 2 (25.00%)grade IV, and 1 (12.50%) in grade V; in Group C: 2 (25.00%)in grade I, 4 (50.00%) in grade II, 2 (25.00%)in grade III, 0 (0.00%)grade IV, and 0 (0.00 %) in grade V; in Group D: 1 (12.50%)in grade I, 4 (50.00%) in grade II, 2 (25.00%) in grade III, 1 (12.50%) grade IV, and 0 (0.00%) in grade V. The difference among Group B-D was statistically significant (. P<0.05). Conclusions: Resveratrol has protective effect on lens epithelial cell apoptosis in diabetic cataract rat, and the effect is relative to its dose.

Development of a DNA microarray for detecting 8 common species of food-borne bacterial pathogens in south China / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a DNA Microarray that can detect 8 common species of food borne bacterial pathogens in south China.</p><p><b>METHODS</b>All the 70mer oligo probes were designed on the characteristic genome loci of the 8 species of food borne bacterial pathogens. Eight subarrays corresponding to the 8 food borne bacterial pathogens were spotted onto the slide and integrated into a pan-array on the chip. A number of identified and known bacterial samples from the storage bank were selected for the validation test.</p><p><b>RESULTS</b>Based on the PPR ranking, for LM sub-array, the PPR of the 3 Listeria bacteria LM, Lin and Liv was 68.8%, 51.8% and 59.6%, respectively, while that of the non-Listeria bacterial samples was all below 43%. For VC sub-array, the PPR of VC sample was 54.1% and that of the non-VC bacterial samples was lower than 17.2%. For VP sub-array, the PPR was 66.7% for VP sample and below 24.2% for non-VP bacterial samples. For Sal sub-array, the PPR was 55.9% for Sal sample and below 50.5% for non-Sal bacterial samples. For Shi sub-array, the PPR of Shi sample and the non-Shi bacterial samples was 53.8% and below 36.6%, respectively. For SA sub-array, the PPR of SA sample and non-SA bacterial samples was 65.2% and below 22.7%, respectively. For CJ sub-array, the PPR of the 2 Campylobacter bacteria CJ and CC were 88.2% and 58.8%, respectively, and that of the non-Campylobacter bacterial samples was lower than 35.3%. For EC sub-array, the PPR of EC sample was 47.9%, and that of the non-EC bacterial samples was lower than 41.6%. Evaluation of the Biosafood-8 chip developed in this study by 18 biological samples from different origins demonstrated its good specificity and accuracy in the identification of the pathogens.</p><p><b>CONCLUSION</b>The chip we developed can clearly differentiate the target food borne pathogenic bacteria and non-target bacteria and allows specific and accurate identification of the species of the tested bacteria isolates.</p>

MLST typing of Streptococcus suis isolated from clinical patients in Guangdong Province in 2005 / 南方医科大学学报

Intensive surveillance of human S.suis infection was carried out in July and August of 2005 in Guangdong Province, which coincided with the Sichuan outbreak. Five isolated cases of human infections were identified during this period, from which 5 S. suis serotype 2 isolates were recovered. MLST analysis showed that these 5 isolates shared identical sequences of 6 MLST housekeeping genes except for one point mutation found within the thrA gene fragment, a neutral mutation (TTA to TTG) in the third nucleotide (360 nt) of the codon for leucine. MLST analysis identified 2 sequence types in the Guangdong sporadic infection. Three Guangdong isolates L-SS002, L-SS003 and L-SS005 belonged to ST7, while the other two isolates L-SS004 and L-SS006 belonged to ST1, but they all belonged to ST1 clonal complex. This finding represents a striking feature that differs from the Sichuan outbreak caused by a single ST7 SS2 clone. The 3 isolates of ST7 were probably imported from Sichuan Province, while the origin of the other 2 isolates of ST1 still remain to be clarified.

Molecular typing of Listeria monocytogenes isolated from foodstuff in Guangdong province by pulsed-field gel electrophoresis / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish molecular typing of Listeria monocytogenes isolates by pulsed-field gel electrophoresis (PFGE) for studying the epidemiologic characteristics of Listeria monocytogenes isolated from foodstuff in Guangdong province and to build up PFGE typing database of Listeria monocytogenes isolates for identifying the infectious resource of the outbreaks and other epidemiologic investigation.</p><p><b>METHODS</b>"Standardized Protocol for Molecular Subtyping of Listeria monocytogenes by PFGE" was followed. BioNumerics software was applied on image analysis, database establishment, comparative and corresponding analysis.</p><p><b>RESULTS</b>107 Listeria monocytogenes isolates were typed by PFGE, 41 PFGE types were observed among the isolates. The PFGE types were dispersive among these isolates. Listeria monocytogenes isolates were most frequently isolated in raw chicken while the most PFGE types were found in this type of food. The positive rate was relatively high in cold and iced foods. Only 1-2 DNA fragment difference occurred in 26 Listeria monocytogenes isolates by PFGE, so high degree of relatedness remained among these isolates. There were unique PFGE patterns in the regions of Shaoguan and Huizhou. From time to time, a number of isolates remained close relationship.</p><p><b>CONCLUSION</b>PFGE typing of the 107 Guangdong Listeria monocytogenes isolates demonstrated relative genetic diversity but a number of the isolates showed close relatedness.</p>