[Effects of different packaging and storage on quality and shelf life of Radix Astragali]

OBJECTIVE

Various treatments were used in packaging and storing dry and fresh Radix Astragali in order to explore an economically practical storage method.

METHOD

The experiment was designed in single-factor completely random as compared with the traditional stacking without package in which the character, quality, polysaccharide and extract contents were measured.

RESULT

If stored for long-term use, the Radix Astragali should be packaged with vacuum-exhausted bags after cleaning by water and dried, which resulted in less weight loss, higher extract and polysaccharide. However, if stored for fresh use, the fresh Radix Astragali should be packaged in vacuum-exhausted bags after cleaning by sorghum alcohol and stored under low temperatures if possible, which resulted in less loss and longer fresh time. Considering polysaccharide and extract content, it is better to use dried the Radix Astragali in storage.

CONCLUSION

Before packaged in vacuum-exhausted bags, the dry Radix Astragali should be cleaned by water for long-term use and cleaned by sorghum alcohol for fresh use under low temperatures if possible.

Modelling periodic oscillation of biological systems with multiple timescale networks

In this paper, we aim to develop a new methodology to model and design periodic oscillators of biological networks, in particular gene regulatory networks with multiple genes, proteins and time delays, by using multiple timescale networks (MTN). Fast reactions constitute a positive feedback-loop network (PFN), while slow reactions consist of a cyclic feedback-loop network (CFN), in MTN. Multiple timescales are exploited to simplify models according to singular perturbation theory. We show that a MTN has no stable equilibrium but stable periodic orbits when certain conditions are satisfied. Specifically, we first prove the basic properties of MTNs with only one PFN, and then generalise the result to MTNs with multiple PFNs. Finally, we design a biologically plausible gene regulatory network by the cI and Lac genes, to demonstrate the theoretical results. Since there is less restriction on the network structure of a MTN, it can be expected to apply to a wide variety of areas on the modelling, analysing and designing of biological systems.

Genome-wide identification of NBS genes in japonica rice reveals significant expansion of divergent non-TIR NBS-LRR genes

A complete set of candidate disease resistance ( R) genes encoding nucleotide-binding sites (NBSs) was identified in the genome sequence of japonica rice ( Oryza sativaL. var. Nipponbare). These putative R genes were characterized with respect to structural diversity, phylogenetic relationships and chromosomal distribution, and compared with those in Arabidopsis thaliana. We found 535 NBS-coding sequences, including 480 non-TIR (Toll/IL-1 receptor) NBS-LRR (Leucine Rich Repeat) genes. TIR NBS-LRR genes, which are common in A. thaliana, have not been identified in the rice genome. The number of non-TIR NBS-LRR genes in rice is 8.7 times higher than that in A. thaliana, and they account for about 1% of all of predicted ORFs in the rice genome. Some 76% of the NBS genes were located in 44 gene clusters or in 57 tandem arrays, and 16 apparent gene duplications were detected in these regions. Phylogenetic analyses based both NBS and N-terminal regions classified the genes into about 200 groups, but no deep clades were detected, in contrast to the two distinct clusters found in A. thaliana. The structural and genetic diversity that exists among NBS-LRR proteins in rice is remarkable, and suggests that diversifying selection has played an important role in the evolution of R genes in this agronomically important species. (Supplemental material is available online at http://gattaca.nju.edu.cn.)

Studies on the development of DNA vaccine against Cysticercus cellulosae infection and its efficacy

DNA vaccine against Cysticercus cellulosae infection was developed and its efficacy was tested. A pair of primers specific to antigen B gene of C. cellulosae was designed which amplified the gene successfully with RT-PCR. The gene was ligated to PV93 vector, and the recombinant of antigen B gene and PV93 was transformed to JM83 cells. The transformed JM83 cells were cultured in a large scale and the plasmid purified. Based on the recombinant plasmid. a DNA vaccine was developed and used to vaccinate two groups of experimental pigs. In each group, there was a routine vaccine, an enhanced vaccine and a control group. Groups 1 and 2 were challenged at 4 months and at 14 days post vaccination respectively with eggs of Taenia solium. The antibody response was also tested with ELISA. The results suggested that all animals vaccinated AgB gene DNA vaccine, no matter by routine or enhanced vaccine, their antibodies reached maximum peak 23 days post vaccination and decreased gradually. When the animals were challenged 4 months after vaccination, they had strong immunity and the parasites decrease rates were 91.2% and 93.1% respectively. When pigs vaccinated with AgB gene DNA vaccine were challenged 14 days post vaccination with 18,000 eggs/pig. The animals showed strong immunity and the parasite decrease rates were 99.5% and 84.9% respectively. However at that time, the antibodies did not reach the peak. While in the control group, the number of C. cellulosae was as many as 2,500. It was concluded that the pigs vaccinated with DNA vaccine had strong immunity against infection of eggs of T. solium.

Public awareness of stuttering in Shanghai, China

This study reports the results of an investigation of knowledge and public awareness of stuttering among laypersons in Shanghai, China. A total number of 1968 respondents answered a questionnaire including questions about prevalence, onset, gender distribution and occurrence in different cultures, cause, treatment, intelligence and heredity of stuttering. Stuttering appears to be a disorder that most people in the Shanghai area are familiar with, and for several aspects a considerable number of respondents held views that are in line with current knowledge about stuttering. For some aspects though knowledge is limited, indicating a need for disseminating scientific information on stuttering. The results of the present study are compared with a similar Belgium study.

Nocistatin, a peptide reversing acute and chronic morphine tolerance

It has been reported that intracerebroventricular (i.c.v.) injection of nociception/orphanin FQ (OFQ) can antagonize morphine analgesia, whereas i.c.v. OFQ antibody can reverse morphine tolerance. Nocistatin (NST) is a recently characterized neuropeptide possessing an antagonizing effect on OFQ. Here we examine whether i.c.v. NST would result in a reversal of morphine tolerance. The results showed that: (1) i.c.v. NST at doses of 0.005, 0.05, 0.5, 5 or 50 ng per rat produced a bell-shaped dose-dependent reversal of chronic morphine tolerance, with maximum response at 0.5 ng. (2) Acute morphine tolerance could also be reversed, albeit partially, by i.c.v. NST at 0.5 ng. (3) The reversal of acute and chronic morphine tolerance by NST was completely abolished when NST (0.5 ng) was co-injected with (8 microg) OFQ. Since OFQ and NST are derived from the same preprohormone, the profile of its splicing in the CNS may play an important role in determining the effectiveness of morphine analgesia.

An evaluation of the colorimetric assays based on enzymatic reactions used in the measurement of human natural cytotoxicity

In recent years colorimetric assays based on an enzymatic reaction such as the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay have been used in an attempt to replace the conventional isotopic assay for cell-mediated cytotoxicity. To clarify the problems in the colorimetric assays for natural cytotoxicity, K562 cells were employed as target cells and peripheral mononuclear cells (PBMCs) from cancer patients were used as effector cells. No correlation was found between the 51Cr assay and the MTT assay (P>0.05) or the N-acetyl-beta-D-glycosaminidase (NAG) release assay (P>0.05) in 16 cancer patients. Labeling effector cells showed that the 51Cr release levels of such cells in 19 chemotherapy patients were significantly higher than the levels from target cells in this group (P<0.01) and from effector cells in the control group (P<0.01). There was no correlation between the positive and negative 51Cr assays (P>0.05). The sensitivity of the MTT assay was greatly decreased by washing K562 cells prior to loading MTT solution. Enzyme release occurs as a result of cell metabolism and elevated enzyme release is associated with freezing. These findings indicate that the colorimetric assays based on an enzymatic reaction are not suitable for the detection of natural cytotoxicity in all populations, and are especially not suitable for the assay of natural cytotoxicity in chemotherapy patients.

[Profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis of rats induced by N, N'dinitrosopiperazine (DNP)]

OBJECTIVE

To investigate the profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis (NPC) induced by N, N'dinitrosopiperazine (DNP) and examined histolofically.

METHODS

Nasopharyngeal carcinomas of rats were induced by DNP and examined histologically. PCR-ELISA and nested RT-PCR were used to assay telomerase and telomerase RNA expression at different stages in the nasopharyngeal tissues of rats.

RESULTS

During the carcinogenesis process, telomerase activity increased along with the formation of a nasopharyngeal carcinoma. Telomerase expression was positively related with nasopharyngeal carcinogenesis. Telomerase RNA expression was present and did not change during the NPC process. Expression of telomease RNA was earlier than telomerase activation. Telomerase activation and telomerase RNA expressin were also detected in the pre-cancerous nasopharyngeal lesions.

CONCLUSION

Telomerase activation may participate in the onset and progression of NPC, and is an early step in NPC.