A novel method to detect circulating antigens of Schistosoma japonicum using a gold nanorod optical sensor

Diagnostic method of Schistosoma japonicum (S.japonicum) is the key of schistosomiasis prevention and control. In China, schistosomiasis reached the stage of transmission control, and almost of the epidemic areas tend to have low infection rate and intensity, but it is difficult for the existing detection methods to achieve accurate monitoring. In this study, a novel method to detect the circulating antigens of S.japonicum using gold nanorods optical sensor was developed. Gold nanorods were prepared by seed-mediated growth followed by deposition onto Indium-Tin-Oxide (ITO) glass to fabricate a solid phase biosensor. In order to assembly between the ITO glass and gold nanorod, hydroxylation and sulfhydrylation were carried out to modify the ITO glass. Surface of gold nanorods was conjugated with an SIEA26-28kDaSjscFv antibody against S.japonicum circulating antigens, and the sensor optical changed upon antigen-antibody recognition. The sensor was used to detect S.japonicum infection in rabbits by testing the serum once a week for 8 weeks. Results revealed different displacement of localized surface plasmon resonance (LSPR) of the gold nanorod optical sensor each week while the control group showed no such change in LSPR. Simultaneously, Indirect Hemagglutination Assay(IHA) and Fast Enzyme-Linked Immuno Sorbent Assay (F-ELISA) method were used to test these samples. Ten human serum samples from S.japonicum infected patients were analyzed using the gold nanorods optical sensor, which revealed that health human serum did not show any spectrum displacement. We developed a specificity gold nanorod optical sensor by combining the SIEA26-28kDaSjscFv, which was used to detect circulating antigens of S.japonicum. This method is expected to overcome the issues pertaining to the testing of circulating antigens of S.japonicum.

[Detection and analysis of alien genes in transgenic rice by fluorescence in situ hybridization]

Using fluorescence in situ hybridization (FISH) with metaphase preparations, we localized a transferred barnase-psl DNA sequence onto chromosomes in 8 rice transgenic plants. All the tested rice transgenic lines showed hybridization signals on the middle and terminal regions of chromosome arms except for those close to centromeres. In two lines, two different integration sites were identified, and the other lines showed only one integration site. With the aid of Southern analysis and expression detection, we found that the barnase tended to show a higher level expression in the lines whose integration sites near the distal regions of chromosomes, while the expression level became lower in the lines whose integration sites near the centromeres. This result suggested a possible relationship between chromosomal location of transgenes and the expression level. However it showed no obvious relationship between copy numbers and expression levels. In most cases, the results of multi-color FISH showed that barnase-ps1 always integrated at the same position on the chrmosome as the reporter genes(pHctinG).

[Physical mapping of the genes px and cld coding peroxidase and cold-regulated protein in maize (Zea mays L.)]

Peroxidase plays a key role in plant disease resistance, cold stress and some developmental processes, and cold-regulated protein functions necessarily in reaction of plants on cold or heat stress. Recent studies showed that these processes in plant cells were involved in programmed cell death (PCD). Using a biotin-labelled in situ hybridization (ISH) technique, we physically mapped the genes px and cld coding peroxidase and cold-regulated protein respectively onto maize chromosomes. Both DAB and fluorescence detection systems gave the identical results, the probe uaz235 corresponding to gene px was localized onto the long arm of chromosome 2 (2L) and 7L, and csu19 corresponding to gene cld was hybridized onto 4L and 5L. The percentage distances (from the hybridization sites to centromeres) of uaz235 in 2L and 7L were 45.4 +/- 1.3 and 67.4 +/- 3.7 respectively, and those of csu19 in 4L and 5L were 68.6 +/- 2.6 and 58.2 +/- 1.6 respectively. The physical positions of px in 2L and cld in 4L coincide with those in their genetic map pattern. The results also show that both of these genes have duplicated sites in maize genome.

[Salt stress-induced apoptosis in plants--a possible resistance mechanism to salt stress]

Previous study has showed that apoptosis-like cell death can be induced under moderate salt stress in plants. In this paper, we studied the cell death induced by salt stress in maize, rice and tobacco roots utilizing DNA Laddering, paraffin sectioning-based TUNEL and chromosome spreading-based TUNEL simultaneously. The characteristic morphological and biochemical features showed apoptosis induced by salt stress may be a universal phenomenon in plants, but some differences may lie in various species. These results provided a valuable insight into studying the physiological mechanism of stress resistance in plants. In addition, we compared the in situ labelling technique based on chromosome spreading with that based on paraffin sectioning. We proposed according to the results that chromosome spreading-based in situ labeling technique should be suitable to detect individual cell death qualitatively and quantitatively with high efficiency, low background and detailed description of apoptotic changes at chromosome, nuclear and DNA levels.

Right ventricular size and ventricular septal motion after repair of atrial septal defect in children

An enlarged right ventricle and abnormal ventricular septal motion are characteristic echocardiographic features of atrial septal defect and often persist after the defect has been completely closed, even when the operation clinically is judged to be successful. These features were examined retrospectively 15 to 21 months after operation in a group of children whose atrial septal defect had been closed between January 1976 and July 1979. Despite satisfactory postoperative results in all, about two thirds had an enlarged right ventricular dimension and about the same number had abnormal septal motion when examined echocardiographically an average of 18 months after operation. The best operative strategy seems to be to operate while the right ventricular end-diastolic dimension is still relatively small in echocardiographic terms.