Taraxasterol acetate targets RNF31 to inhibit RNF31/p53 axis-driven cell proliferation in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide. Several studies have suggested that taraxasterol acetate (TA) can inhibit the growth of tumor cells. However, to date, it remains unclear how TA inhibits cell growth and how RNF31 functions as an oncogene. We examined the expression of RNF31 in CRC tissue samples via immunohistochemistry and elucidated the function of RNF31 in CRC cells by constructing a cell model with RNF31 depletion. A cycloheximide (CHX)-chase analysis and immunofluorescence assays were conducted to demonstrate that TA can promote RNF31 degradation by activating autophagy. We used the PharmMapper website to predict targets of TA and identified RNF31. CHX-chase experiments showed that TA could facilitate RNF31 degradation, which was inhibited by the administration of chloroquine. Immunofluorescence assays showed that RNF31 protein was colocalized with LC3I/II and p62, suggesting that TA promoted RNF31 degradation by activating autophagy. We also found that CRC patients with RNF31 overexpression had poorer survival than those with low RNF31 expression. The results of the CHX-chase experiment showed that depletion of RNF31 alleviated p53 degradation, which was inhibited by MG132. A series of co-immunoprecipitation (Co-IP) assays revealed that RNF31 interacts with p53 and promotes p53 ubiquitination and degradation. A Co-IP assay performed with a truncated RNF31 plasmid showed that the PUB domain interacts with p53. Moreover, the PUB domain is the key structure in the induction of p53 ubiquitination. Our findings reveal a key role of RNF31 in CRC cell growth and indicate a mechanism through which TA inhibits cell growth.

Long noncoding RNA SNHG8 promotes the proliferation of osteosarcoma cells by downregulating miR-542-3p

Small nucleolar RNA host genes (SNHGs) as a subset of long noncoding RNAs (lncRNAs) have critical roles in the pathogenesis of multiple malignancies, however, the role and molecular mechanisms of lncRNA SNHG8 in osteosarcoma (OS) remain unclear. In the present study, the correlation of SNHG8 or miR-542-3p with clinicopathological elements and prognosis in OS patents was estimated by TCGA cohort. Cell viability and invasion were assessed by MTT and Transwell assays. The interplay between SNHG8 and miR-542-3p was affirmed by a luciferase report assay. The effects of SNHG8 on miR-542-3p expression were examined in MG-63 and SW-1353 cells by qRT-PCR analysis. The results showed that incremental expression of SNHG8 or reduced expression of miR-542-3p was related to poor survival and tumor recurrence in OS patients. Overexpressing SNHG8 accelerated the growth and invasion of MG-63 cells, but silencing SNHG8 harbored an opposite effect in SW-1353 cells. Additionally, SNHG8 could negatively regulate miR-542-3p expression and bind with miR-542-3p, which attenuated SNHG8 induced cell proliferation. Taken together, these findings indicate that lncRNA SNHG8 promotes the proliferation of OS cells by downregulating miR-542-3p.

Knockdown of microRNA-103a-3p inhibits the malignancy of thyroid cancer cells through Hippo signaling pathway by upregulating LATS1

MicroRNA (miR)-103a-3p has been shown to be involved in the development and progression of several types of cancer. However, the role of miR-103a-3p in thyroid cancer remains unclear. This study investigated the effects of miR-103a-3p on the biological characteristics of thyroid cancer cells and related mechanisms. In the present study, we found that the expression of miR-103a-3p was increased in thyroid cancer tissues compared to that in non-cancerous tissues. Additionally, the expression of miR-103a-3p in thyroid cancer cell lines (TPC-1, SW579, BHT101, K1) was markedly higher than that in the human thyroid cell line (Nthy-ori3-1). Silencing of miR-103a-3p obviously inhibited proliferation, migration, and invasion and promoted apoptosis of BHT101 cells. miR-103a-3p upregulation promoted the proliferation, migration, and invasion and inhibited apoptosis of K1 cells. Mechanistically, LATS1 was identified as a functional target of miR-103a-3p, and miR-103a-3p negatively regulated LATS1 expression. miR-103a-3p knockdown (or upregulation) partially reversed the effects of LATS1 knockdown (or overexpression) on proliferation, apoptosis, migration, and invasion of thyroid cancer cells. LATS1 knockdown inhibited the phosphorylation of YAP in BHT101 cells and promoted the nuclear translocation of YAP. Whereas, miR-103a-3p downregulation reversed the inhibitory effect of LATS1 knockdown on the Hippo signaling pathway. Moreover, overexpression of LATS1 induced YAP phosphorylation in K1 cells and inhibits nuclear translocation of YAP, and the upregulation of miR-103a-3p reversed this effect. The knockdown of miR-103a-3p inhibited tumor growth and progression in vivo. Taken together, knockdown of miR-103a-3p inhibits proliferation, migration, and invasion and promotes apoptosis of thyroid cancer cells through the Hippo signaling pathway by upregulating LATS1.

[Study on the effect of diallyl sulfide on peripheral nerve injury in n-hexane intoxicated rats]

Objective: To investigate the antagonistic effect of diallyl sulfide (DAS) against peripheral nerve injury induced by n-hexane in rats. Methods: A total of 68 adult male Wistar rats were selected, among which 50 were randomly selected and divided into blank control group, DAS control group (100 mg/kg·bw) , n-hexane model group, low-dose DAS intervention group (50 mg/kg·bw) , and high-dose DAS intervention group (100 mg/kg·bw) . A rat model of peripheral nerve injury was established by n-hexane exposure, and the rats were treated with DAS at different doses. The changes in pyrrole adducts and behavior were observed, a metabolic analysis was performed for serum pyrrole adducts, and the intervention effect was evaluated. The remaining 18 rats were randomly assigned to the n-hexane model group, the low-dose DAS intervention group, and the high-dose DAS intervention group, with 6 rats in each group, as satellite groups used for the toxicokinetic analysis of serum pyrrole adducts. Results: Compared with the blank control group, the n-hexane model group and low-and high-dose DAS intervention groups had a significant reduction in body weight since week 2 (P<0.01) . Compared with the n-hexane model group at the end of the experiment at week 7, the high-dose DAS intervention group had a significantly higher body weight (P<0.05) , while there was no significant difference in body weight between the n-hexane model group and the low-dose DAS intervention group (P>0.05) . The n-hexane model group developed gait abnormality at week 2 of poisoning, while the low-and high-dose DAS intervention groups developed gait abnormality at weeks 3 and 5 of poisoning, respectively. At the end of the experiment, the n-hexane model group and the low-and high-dose DAS intervention groups had a significantly higher gait score than the blank control group (P<0.01) . At the end of the experiment, the n-hexane model group and the low-dose DAS intervention group had significantly shorter latency in rotarod test than the blank control group (P<0.01) , while there was no significant difference in latency between the DAS control group and the high-dose DAS intervention group (P>0.05) . Compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in latency in rotarod test (P<0.01) . Compared with blank control group, the n-hexane model group and the low-dose DAS intervention group had a significant increase in mean nerve conduction velocity (P<0.01) , while there was no significant difference between the blank control group and the DAS control group or high-dose DAS intervention group (P>0.05) , and compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in nerve conduction velocity (P<0.01) . Compared with the blank control group at the end of the experiment at week 7, the n-hexane model group and the low-and high-dose DAS intervention groups had significant increases in the concentration of pyrrole adducts in serum, urine, and hair (P<0.01) , while there was no significant difference between the blank control group and the DAS control group (P>0.05) , and the high-dose DAS intervention group had a significantly lower concentration of pyrrole adducts in serum, urine, and hair than the low-dose DAS intervention group (P<0.05) . Serum pyrrole adducts reached the peak level at 9-12 hours and then started to decrease. Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significantly shorter half-life period of serum pyrrole adducts (P<0.01) . Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significant reduction in the area under the curve of serum pyrrole adducts (P<0.05) . Conclusion: DAS can antagonize peripheral nerve injury induced by n-hexane.

[Antioxidant mechanism of diallyl sulfide in inhibiting leucopenia in peripheral blood induced by benzene in rats]

Objective: To investigate the antioxidant mechanism of diallyl sulfide (DAS) in antagonizing the reduction in peripheral blood white blood cells (WBC) induced by benzene in rats. Methods: A total of 60 specific pathogen-free adult male Sprague-Dawley rats, with a body weight of 180-220 g, were selected, and after 5 days of adaptive feeding, they were randomly divided into blank control group, DAS control group, benzene model group, benzene+low-dose DAS group, benzene+middle-dose DAS group, and benzene+high-dose DAS group, with 10 rats in each group. The rats in the benzene+low-dose DAS group, the benzene+middle-dose DAS group, the benzene+high-dose DAS group, and the DAS control group were given DAS by gavage at a dose of 40, 80, 160, and 160 mg/kg·bw, respectively, and those in the blank control group and the benzene model group were given an equal volume of corn oil; 2 hours later, the rats in the benzene model group, the benzene+low-dose DAS group, the benzene+middle-dose DAS group, and the benzene+high-dose DAS group were given a mixture of benzene (1.3 g/kg·bw) and corn oil (with a volume fraction of 50%), and those in the blank control group and the DAS control group were given an equal volume of corn oil. The above treatment was given once a day for 4 consecutive weeks. At 1 day before treatment, anticoagulated blood was collected from the jugular vein for peripheral blood cell counting. After anesthesia with intraperitoneally injected pentobarbital (50 mg/kg·bw), blood samples were collected from the abdominal aorta, serum was isolated, and the thymus, the spleen, and the femur were freed at a low temperature to measure oxidative and antioxidant indices. The femur at one side was freed for WBC counting in bone marrow. Results: Compared with the blank control group, the benzene model group had significant reductions in the volume, weight, and organ coefficient of the spleen and the thymus (P<0.05) ; compared with the benzene model group, the benzene+low-dose DAS group, the benzene+middle-dose DAS group, and the benzene+high-dose DAS group had significant increases in the volume of the spleen and the thymus and the weight and organ coefficient of the spleen (P<0.05), and the benzene+middle-dose DAS group and the benzene+high-dose DAS group had significant increases in the weight and organ coefficient of the thymus (P<0.05). Compared with the blank control group, the benzene model group had a significant reduction in WBC count in peripheral blood and bone marrow (P<0.05), and compared with the benzene model group, the benzene+middle-dose DAS group and the benzene+high-dose DAS group had a significant increase in WBC count in peripheral blood and bone marrow (P<0.05). Compared with the blank control group, the benzene model group had a significant increase in the serum level of malondialdehyde (MDA) (P<0.05) and significant reductions in total superoxide dismutase (T-SOD) activity, reduced glutathione (GSH) level, GSH/oxidized glutathione (GSSG) ratio, total antioxidant capacity (T-AOC) (P<0.05) ; compared with the benzene model group, the benzene+high-dose DAS group had a significant reduction in the serum level of MDA and significant increases in T-SOD activity, GSH level, GSH/GSSG ratio, and T-AOC (P<0.05). Compared with the blank control group, the benzene model group had a significant increase in the level of MDA (P<0.05) and significant reductions in GSH level, GSH/GSSG ratio, and T-AOC (P<0.05) in the spleen; compared with the benzene model group, the benzene+low-dose DAS group, the benzene+middle-dose DAS group, and the benzene+high-dose DAS group had a significant reduction in MDA level (P<0.05) and significant increases in GSH level and T-AOC (P<0.05), and the benzene+high-dose DAS group had significant increases in T-SOD activity and GSH/GSSG ratio (P<0.05). Compared with the blank control group, the benzene model group had a significant increase in the level of MDA in bone marrow cells (BMCs) and peripheral blood mononucleated cells (PBMCs) (P<0.05) and a significant reduction in T-AOC in PBMCs (P<0.05) ; compared with the benzene model group, the benzene+low-dose DAS group, the benzene+middle-dose DAS group, and the benzene+high-dose DAS group had a significant reduction in the level of MDA in BMCs and PBMCs (P<0.05), and the benzene+high-dose DAS group had significant increases in GSH level and GSH/GSSG ratio (P<0.05) . Conclusion: DAS can antagonize the benzene-induced reduction in peripheral blood WBC, possibly by exerting an anti-oxidative stress effect.

[Effect of biofeedback therapy on metabolic syndrome under different levels of job stress]

Objective: To investigate the effect of biofeedback therapy on metabolic syndrome (MS) and the effect of different levels of job stress on the outcome. Methods: The physicians in tertiary hospitals who were diagnosed with MS from January to December, 2016 were divided into biofeedback group and health education group according to different intervention methods, and moderate group, medium group, and high group according to different levels of job stress. A 6-month intervention was implemented from May to October, 2017. A two-way factorial design was used to analyze the main effect of biofeedback on physical and biochemical parameters and the interaction of biofeedback and job stress. Results: After 6 months of intervention, the patients in both the biofeedback group and the moderate group had significantly decreased waist circumference, body mass index, systolic blood pressure (SBP) , diastolic blood pressure (DBP) , and levels of triglyceride (TG) , total cholesterol, low-density lipoprotein cholesterol (LDL-C) , and fasting plasma glucose (FPG) and a significantly increased level of high-density lipoprotein cholesterol (HDL-C) (all P<0.05) ; the patients in both the health education group and the moderate group had significantly decreased SBP, DBP, and levels of TG, LDL-C, and FPG (P<0.05) . The factorial analysis of variance showed that there was a synergistic interaction between the intervention method and job stress level in SBP, DBP, TG, HDL-C, LDL-C, and FPG among MS patients (P<0.05) . The high group had significantly more improvements in all indices compared with the medium group and the moderate group (P<0.05) . Conclusion: Biofeedback therapy can effectively improve blood pressure, blood lipids, and blood glucose in MS patients, and is more effective for patients with high job stress level.

[Characteristics and drug resistance of non-O157 Shiga toxin-producing E. coli in animal feces, from Shandong Province]

Objective: To understand the infection status, characteristics and drug resistance of non-O157 Shiga toxin-producing E. coli (STEC) in animal feces in Shandong Province. Methods: From 2015 to 2016, convient sampling method was used to collect 1 022 fresh feces of animals in Weishan county and Laizhou city, and 24 non-O157 STEC were isolated. The serotypes of non-O157 STEC strains were confirmed through serum agglutination test. The susceptibility was explored through the antimicrobial sensitivity experiments. ESBLs activity was confirmed by double-disc diffusion. PCR method was used to detect the resistance genes. PFGE typing was operated to assess the relatedness and variability of the strains. The multi-locus sequence typing (MLST) was adopted to get the allelic profile and ST sequence of strains. Analysis was made on the evolutionary relationship between different ST groups was made through CLC Sequence Viewer and Counting Express. Results: A total of 24 non-O157 STEC were isolated from animal feces. 23 strains were from pig feces, and 1 strain was from cow feces, and the serotypes were more dispersed. All of the 24 strains carried stx2 genes. The highest resistance rate was sulfamethoxazole(22 strains), the mount of cotrimoxazole and nalidixic acid was 18 strains, chloramphenicol was 13 strains, tetracycline was 19, and there was a phenomenon of multiple drug resistance. The drug resistance spectrum was sulfamethoxazole tetracycline-compound novammin-naphthidine-chloramphenicol. All strains were sensitive to cefepime and imipenem. The ESBLs confirmatory test showed that 4 strains of non O157 STEC produced beta lactamase. PCR detected 7 resistance genes, and 4 tetracycline resistance genes (Tet A, Tet B, tetC and tetD) were detected. The beta lactamase resistance genes (blaSHV-1, bla CTX-M, bla TEM) were all negative. 24 strains were divided into 15 PFGE types, and their clustering results were more dispersed and no dominant PFGE type. There were 11 kinds of MLST types, most of them are ST540 and ST5133 types, each of which was 4 strains, and clustered into 1 MLST genomes. Conclusion: The serotypes of non-O157 STEC in animal feces O157 STEC were dispersed, and the resistant rate to common antibiotic was high. MLST typing results presents obvious polymorphism. Surveillance and manage ment of these strains should be strengthened.

["Time-angle measurement" reduction evaluation technique and clinical evaluation of proximal humerus fracture]

OBJECTIVE

To evaluate the functional outcome and the complication rate after open reduction and internal fixation of proximal humeral fractures with a "time-angle measurement" reduction evaluation technique, to assess the acceptance of the fracture reduction and to estimate the result of the sur-gery.

METHODS

Forty-six patients [mean age: (66.2±14.9) years] with an acute proximal humeral fracture were managed with open reduction and internal fixation with this reduction evaluation technique from January 2012 to December 2013. According to the Neer classification, there were 6 two- part fractures, 25 three-part fractures and 15 four-part fractures. The functional outcome was evaluated for each patient using the Constant-Murley score; radiographic evaluation was also conducted and complications were recorded. The postoperative shoulder function recovery and imaging findings were followed up to evaluate the guiding significance of this reduction evaluation technique in the clinical treatment of this kind of fracture.

RESULTS

In the study, 46 patients had been followed up for 13-36 months, and the average follow-up time was (23.5±7.3) months. All the patients achieved fracture healing 3 months after operation. The average head-shaft angle was (124±3.5) degrees. According to the Constant scoring system, 29 patients (63%) had excellent, 14 patients (30%) had good, and 3 patients (7%) had poor results. The most common complications were pain (7/65) and restricted movement of the shoulder (5/46). There were no cases of screw penetration, necrosis of humeral head, deep tissue infection, nonunion of fracture and axillary nerve injury after operation.

CONCLUSION

For appropriate cases of displaced proximal humeral fractures, surgical treatment with application of "time-angle measurement" reduction evaluation technique that was introduced in the present study can lead to a good functional outcome, and the technique of reduction assessment should be regarded as a reasonable reference standard in the treatment of displaced proximal humerus fracture.

Quantitative trait locus analysis of grape weight and soluble solid content

A grapevine hybrid population was derived from a crossing of the early-maturing female parent cultivar '87-1' and the late-maturing male parent cultivar '9-22'. A total of 149 plants were selected from the hybrid population as the mapping population, and after sequence-related amplified polymorphism and simple-sequence repeat marker analysis were conducted we constructed molecular genetic maps of the parents. The molecular linkage map of '87-1' had 19 linkage groups that contained 188 markers, with an average interval of 5.7 cM and a total distance of 1074.5 cM; the '9-22' map had 19 linkage groups that contained 175 markers, with an average interval of 7.8 cM and a total distance of 1100.2 cM. The molecular linkage map of both parents had 19 linkage groups that contained 251 markers, with an average interval of 5.0 cM and a total distance of 1264.2 cM. We used the interval mapping method to conduct a quantitative trait locus (QTL) analysis of grape weight and soluble solid content of the mapping population. Six QTLs were related to grape weight, and the average contribution to the phenotypic variance was between 11.3 and 33.0%. Seven QTLs were related to soluble solid content, and the average contribution to the phenotypic variance was between 15.7 and 55.8%.

Role of chemokines in promoting instability of coronary atherosclerotic plaques and the underlying molecular mechanism

Our aim was to investigate the role of chemokines in promoting instability of coronary atherosclerotic plaques and the underlying molecular mechanism. Coronary angiography and intravascular ultrasound (IVUS) were performed in 60 stable angina pectoris (SAP) patients and 60 unstable angina pectoris (UAP) patients. The chemotactic activity of monocytes in the 2 groups of patients was examined in Transwell chambers. High-sensitivity C-reactive protein (hs-CRP), monocyte chemoattractant protein-1 (MCP-1), regulated on activation in normal T-cell expressed and secreted (RANTES), and fractalkine in serum were examined with ELISA kits, and expression of MCP-1, RANTES, and fractalkine mRNA was examined with real-time PCR. In the SAP group, 92 plaques were detected with IVUS. In the UAP group, 96 plaques were detected with IVUS. The plaques in the UAP group were mainly lipid 51.04% (49/96) and the plaques in the SAP group were mainly fibrous 52.17% (48/92). Compared with the SAP group, the plaque burden and vascular remodeling index in the UAP group were significantly greater than in the SAP group (P<0.01). Chemotactic activity and the number of mobile monocytes in the UAP group were significantly greater than in the SAP group (P<0.01). Concentrations of hs-CRP, MCP-1, RANTES, and fractalkine in the serum of the UAP group were significantly higher than in the serum of the SAP group (P<0.05 or P<0.01), and expression of MCP-1, RANTES, and fractalkine mRNA was significantly higher than in the SAP group (P<0.05). MCP-1, RANTES, and fractalkine probably promote instability of coronary atherosclerotic plaque.

The correlation between vertebral wedge-shaped changes in X-ray imaging at supine and standing positions and the efficacy of operative treatment of thoracolumbar spinal fracture in the elderly

STUDY DESIGN

By analyzing a large number of surgical patients, we identified the roles of wedge-shaped changes in related surgeries.

OBJECTIVES

To illustrate the relevance of vertebral wedge-shaped changes in X-ray imaging at supine and standing positions in patients with percutaneous kyphoplasty as well as the postoperative effect.

SETTING

All patient data were collected from a hospital in China.

METHODS

Between June 2006 and May 2010, 77 surgical patients (9 men and 68 women) with wedge-shaped compression fractures were retrospectively analyzed. Patients were divided into group A (ΔWR2.5%) and group B (ΔWR<2.5%) according to the dynamic changes in the percentage of vertebral body wedge-shaped variable ratio (WR) at supine and standing positions. The intensity of back pain in different positions pre- and postoperatively was evaluated with a visual analog pain scale (VAS).

RESULTS

The WRs in both standing and supine positions were significantly reduced by kyphoplasty in both groups A and B. In agreement with the improvement in WRs, the VAS was significantly decreased in three positions for patients in group A and in turning over and standing position for patients in group B. With respect to ΔWR changes, group B revealed significantly lower values compared with group A preoperatively (P<0.001), but there was no significant difference between groups A and B postoperatively and at 1-month follow-up (P=0.179 and P=0.558, respectively).

CONCLUSIONS

Improvement in symptoms after kyphoplasty is better in patients with wedge-shaped changes in supine and standing positions, and the efficacy of height restoration of the spine would be better in unstable vertebrae by balloon dilatation.

Improving energy accumulation of microbial fuel cells by metabolism regulation using Rhodoferax ferrireducens as biocatalyst

AIMS

To study the physiology and metabolism of microbial cells in the performance of microbial fuel cells (MFCs).

METHODS AND RESULTS

A dual-chamber MFCs was constructed, and Rhodoferax ferrireducens was used as biocatalyst. To examine the physiology of microbial cells in the performance of MFCs, the anode media containing planktonic cells was replaced with fresh media in which KH(2)PO(4) and/or NH(4)Cl were excluded. The replacing of anode media containing planktonic cells with fresh media excluded of KH(2)PO(4) and NH(4)Cl made the coulombic yield remarkably increased by a factor of 68% (from 29.1 to 46.8C). The results showed that the electricity could be generated with cells in biofilms as biocatalyst, and coulombic yield was improved by limiting cell growth via removal of ingredients in anode media. By supplementation of glucose to the anode media when current declined to baseline, MFCs achieved about same platform current values immediately. MFCs could continue to produce electricity for about 30 h even after glucose was below detection.

CONCLUSIONS

Biofilms and metabolism of glucose play important roles in the performance of MFCs. Coulombic yield of MFCs could be improved by regulating the media ingredients using the stable biofilms-electrode system.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first attempt to study the effect of ingredient compositions of anode media on the performance of MFCs. The observed results that MFCs continued to produce electricity after glucose was below detection was helpful to better understand the mechanism of microbial electricity production.

Characterization of two isomeric beta-d-glucosiduronic acids derived from 1,2-diethyl-3-hydroxypyridin-4-one (CP94) in rat liver homogenate incubates

1,2-Diethyl-3-hydroxypyridin-4-one (CP94) is an orally active iron chelator with potential for use in photodynamictherapy. This investigation reports the formation and characterization of two isomeric glucuronides of CP94 in rat liver homogenate incubates. To assign the glucuronidation sites in the CP94 molecule, two O-methylated derivatives of CP94 have been synthesized. By comparing the spectral characteristics of the CP94 3-O- and 4-O-methyl derivatives with CP94 and the CP94 glucuronides formed during incubation, evidence was obtained which enabled the assignment of these two isomeric glucuronides to the 3-O-glucuronide and 4-O-glucuronide of CP94. It was found that the 3-O-glucuronide was the dominant CP94 metabolite under in-vitro conditions. In an attempt to understand the potential influence of structural variation on the glucuronidation of CP94 analogues, the 1-and 2-monoethyl derivatives of CP94 were investigated. The 2-monoethyl derivative of CP94 yielded only the 3-O-glucuronide in rat liver homogenate incubate, while no glucuronide was formed from the 1-monoethyl derivative. In addition, no glucuronide from the 3-O-methyl or 4-O-methyl derivatives of CP94 could be detected. The relevance of these findings to the development of new 3-hydroxypyridin-4-one iron chelators is discussed.

Structure-function investigation of the interaction of 1- and 2-substituted 3-hydroxypyridin-4-ones with 5-lipoxygenase and ribonucleotide reductase

The structural and physiochemical properties of 3-hydroxypyridin-4-one chelators (HPOs) which influence inhibition of the iron-containing metalloenzymes ribonucleotide reductase (RR) and 5-lipoxygenase (5-LO) have been investigated. HPOs with substituents at the 1- and 2-positions of the pyridinone ring have been synthesized, and their inhibitory properties compared with those of desferrioxamine (DFO). Varying the alkyl substituents does not affect the affinity constant of these ligands for iron(III), but permits a systematic investigation of the effect of hydrophobicity and molecular shape on inhibitory properties. The inhibition of RR was monitored, indirectly by measuring tritiated thymidine incorporation into DNA and directly by the quantification of the EPR signal of the enzyme tyrosyl radical. 5-LO inhibition was examined spectrophotometrically, measuring the rate of linoleic hydroperoxide formation by soybean lipoxygenase. The results indicate that the substituent size introduced at the 2-position of the HPO ring is critical for determining inhibition of both enzymes. Large substituents on the 2-position, introduce a steric factor which interferes with accessibility to the iron centers. These studies have identified chelators such as 1,6-dimethyl-2-(N-4',N-propylsuccinamido)methyl-3-hydroxypyridin-4-one (CP358), which causes only a 10% inhibition of 5-LO after 24 h of incubation at 110 microm IBE (iron-binding equivalents) in comparison to simple dialkyl HPOs such as Deferiprone (CP20) which cause up to 70% inhibition. Using EPR spectroscopy, CP358 inhibits RR at a slower rate than CP20, while chelating intracellular iron(III) at a similar rate, a finding consistent with an indirect inhibition of the tyrosyl radical. However, hepatocellular iron is mobilized at a faster rate by CP358 (P < 0.001). These findings demonstrate that it is possible to design bidentate HPOs which access intracellular iron pools rapidly while inhibiting non-heme iron-containing enzymes relatively slowly, at rates comparable to DFO. It is anticipated that such compounds will possess a superior therapeutic safety margin to currently available bidentate HPOs.

[The characteristics of Bacillus thuringiensis strain YBT833 and its transformants that containing different ICP genes]

Four different transformants were selected by transferring cry1C into Bacillus thuringiensis strain YBT833. Southern blot and Plasmid profiles results all proved that cry1C was transferred into strain YBT833. However, it was found by PCR analysis that transformant YBT833-1 kept all indigenous ICP(insecticidal crystal protein) genes of strain YBT833 while transformant YBT833-2 lost cry1Ab, and transformant YBT833-3 lost all ICP genes. SDS-PAGE showed that transformants of YBT833-1, YBT833-2 and YBT833 all had 130 kDa and 65 kDa peptide bands, but transformant YBT833-3 did not have 65 kDa peptide band. Bioassay results showed that the toxicities of all transformants to Spodoptera exigua, Heliothis armigera and Plutella xylostella were lower than that of strain YBT833, except the toxicity of transformant YBT833-2 to P. xylostella which was obviously higher than that of YBT833.

[Cloning of plasmid pBMB2062 in Bacillus thuringiensis strain YBT-1520 and construction of plasmid vector with genetic stability]

A small plasmid pBMB2062 in Bacillus thuringiensis strain YBT-1520 was cloned and sequenced. Its 2,062 bp sequence contains two potential open reading frames (orfs). The orf1 and orf2 encode a tentative replication initial protein consisting of 289 amino acid residues and a tentative replication protein consisting of 80 amino acid residues, respectively. Two homological plasmids were found by Blast searching. There are 23 nucleotides difference occurring among three of the plasmids. The difference occurred in the orf1 causes different encoding capability. Comparing with the orf1 in pBMB2062, the orf1 in the homological plasmids are truncated, one at the N-terminal and another at the C-terminal. cDNA synthesis and PCR detection showed that the mRNA corresponding to orf1 in pBMB2062 really occurs. Shuttle vectors were constructed based on pBMB2062 and showed the ability to express insecticidal crystal gene. Under nonselective condition, recombinant plasmids based on pBMB2062 were genetically stable.

Synthesis of 2-amido-3-hydroxypyridin-4(1H)-ones: novel iron chelators with enhanced pFe3+ values

The synthesis of a range of 2-amido-3-hydroxypyridin-4-ones as bidentate iron(III) chelators with potential for oral administration is described. The pKa values of the ligands together with the stability constants of their iron(III) complexes have been determined. Results indicate that the introduction of an amido substituent at the 2-position leads to an appreciable enhancement of the pFe3+ values. The ability of these novel 3-hydroxypyridin-4-ones to facilitate the iron excretion in bile was investigated using a 59Fe-ferritin loaded rat model. The optimal effect was observed with the N-methyl amido derivative 15b, which has an associated pFe3+ value of 21.7, more than two orders of magnitude higher than that of deferiprone (1,2-dimethyl-3-hydroxypyridin-4-one) 1a (pFe3+ = 19.4). Dose response studies suggest that chelators with high pFe3+ values scavenge iron more effectively at lower doses when compared with simple dialkyl substituted hydroxypyridinones.

Structure-activity investigation of the inhibition of 3-hydroxypyridin-4-ones on mammalian tyrosine hydroxylase

3-Hydroxypyridin-4-ones are currently one of the main candidates for the development of orally active iron chelators. Small bidentate ligands tend to inhibit iron-containing metalloenzymes and therefore can cause undesirable side effects. A range of 3-hydroxypyridin-4-ones with different R2 substituents was selected for the investigation of the structure-activity relationship between the chemical nature of the ligand and the inhibition of mammalian tyrosine hydroxylase. Results indicated that lipophilicity was the dominant factor in controlling the ability of this class of chelator to inhibit mammalian tyrosine hydroxylase. Ligands with hydrophilic R2 substituents tended to be weak inhibitors. No significant correlation was found in this study between iron-binding affinity, extended R2 chain length, and enzyme inhibitory activity. In contrast, both the LogP values of the entire molecule and of the R2 segment correlated well with inhibitory activity.

[Transfer of cry1C gene into Bacillus thuringiensis by electroporation to construct strain with broader insecticidal activity]

Three Transformants were selected by transferring cry1C into Bacillus thuringiensis strain YBT1535. Plasmid profiles, PCR and Southern blot result all proved that cry1C had been transferred into strain YBT1535. Bioassay results showed that the transformants of strain YBT1535 displayed significantly higher toxicity against Spodoptera exigua than strain YBT1535, but the toxicities against Heliothis armigera and Plutella xylostella did not rise except transformant YBT1535-2.

Biliary and urinary metabolic profiles of 1,2-diethyl-3-hydroxypyridin-4-one (CP94) in the rat

This study compares the biliary and urinary metabolic profiles of 1,2-diethyl-3-hydroxypyridin-4-one (CP94), an orally active iron chelator, in the normal rat. Surprisingly, CP94 was found to form two phase II metabolites, the 3-O- and 4-O-glucuronides. These glucuronides accounted for 38 and 28% of the administered CP94 dose, in bile and urine, respectively. Unchanged CP94 accounted for 5% of the CP94 dose in both bile and urine. The 2-(1'-hydroxy) metabolite of CP94 was found to be the dominant metabolite in urine. In addition, an unstable metabolite was detected in the bile although its structure remains unknown at the present stage. The excretion of iron in bile, after administration of CP94, was found to parallel the biliary elimination of CP94 together with its hydroxylated derivatives, indicating the importance of metabolites in iron excretion.

Hydrolytic and metabolic characteristics of the esters of 1-(3'-hydroxypropyl)-2-methyl-3-hydroxypyridin-4-one (CP41), potentially useful iron chelators

1-(3'-Hydroxypropyl)-2-methyl-3-hydroxypyridin-4-one (CP41) has been extensively investigated as an orally effective iron chelator. In order to improve the pharmacokinetic and metabolic properties of CP41, eleven aromatic esters have been synthesised and tested as potential prodrugs. In the present study, the hydrolytic rates of these CP41 esters in phosphate buffer (pH2.0 and pH 7.4), rat blood and rat liver homogenate have been determined and found to cover a wide range. Generally, they possessed relatively slow hydrolytic rates in phosphate buffer (0-50 nmol/ml/hr at pH 2.0 and 0-140 nmol/ml/hr at pH 7.4). The hydrolytic rates in rat blood fell in the range of 9-5766 nmol/ml blood/hr and in rat liver homogenate 1-800 micromol/g liver tissue/hr. All esters possess a higher lipophilicity than that of the parent compound CP41. Although no apparent relationship was observed between the lipophilicities and hydrolytic rates, the esters with relatively higher hydrolytic rates in liver homogenate tend to possess higher iron scavenging efficacies. Further investigation of the metabolism of selected CP41 esters indicates that metabolism is a key factor influencing the efficacy of CP41 esters, as some esters can be metabolically inactivated in the liver in preference to undergoing ester hydrolysis. Ester design, combined with a knowledge of the prodrug metabolism, is a useful strategy for the production of 3-hydroxypyridin-4-ones with enhanced iron scavenging efficacy.

Design, synthesis, and biological evaluation of aromatic ester prodrugs of 1-(3'-hydroxypropyl)-2-methyl-3-hydroxypyridin-4-one (CP41) as orally active iron chelators

In order to improve chelation efficacy and to minimise toxicity, eleven aromatic ester prodrugs of 1-(3'-hydroxypropyl)-2-methyl-3-hydroxypyridin-4-one (CP41) have been synthesised. The distribution coefficients of these ester prodrugs between 1-octanol and MOPS buffer pH 7.4 were measured together with their rates of hydrolysis at pH 2 and pH 7.4, in rat blood and liver homogenate. The biliary metabolic profiles of selected ester prodrugs were investigated in rats. The in vivo iron mobilisation efficacy of these ester prodrugs has been compared with that of the parent drug using a 59Fe-ferritin loaded rat model. The hydrolytic rates of these esters vary appreciably, esters with heteroaromatic acid moieties being less stable than the corresponding benzoyl analogues. Many prodrugs were found to enhance the ability of the parent hydroxypyridinone to facilitate 59Fe excretion, the optimal effect being observed with the 4-methylbenzoyl ester derivative 8d. However, not all prodrugs provide an increased efficacy, indicating that lipophilicity is not the only factor which influences drug efficacy. Furthermore no clear correlation between lipophilicity, susceptibility towards hydrolysis and efficacy was detected.

Design, synthesis and evaluation of N-basic substituted 3-hydroxypyridin-4-ones: orally active iron chelators with lysosomotrophic potential

To investigate the possibility of targeting chelators into the lysosomal iron pool, nine bidentate 3-hydroxypyridin-4-ones with basic chains have been synthesized. As the turnover of ferritin iron is centred in the lysosome, such strategy is predicted to increase chelator efficacy of bidentate ligands. The pKa values of the ligands together with their distribution coefficients between 1-octanol and 4-morpholinepropane sulphonic acid (MOPS) buffer pH 7.4 have been determined. The in-vivo iron mobilization efficacy of these basic 3-hydroxypyridin-4-ones has been investigated in a 59Fe-ferritin-loaded rat model. No obvious correlation was observed between efficacy and the pKa value of the side chain, although those with pKa > 7.0 tended to be more efficient than those with pKa < 7.0. The imidazole-containing molecules are much less effective than the tertiary amine derivatives. A dose-response study suggested that basic pyridinones are relatively more effective at lower doses when compared with N-alkyl hydroxypyridinones. Optimal effects were observed with the piperidine derivatives 4h and 4i. The derivative 4i at a dose of 150 micromol kg(-1) was more effective than 450 micromol kg(-1) deferiprone, the widely adopted clinical dose.

Liquid extraction and ion-pair HPLC for determination of hydrophilic 3-hydroxypyridin-4-one iron chelators

Hydrophilic 3-hydroxypyridin-4-ones (HPOs), such as 1-(2'-carboxyethyl)-2-methyl-3-hydroxypyridin-4-one (CP38), 1-(3'-hydroxypropyl)-2-methyl-3-hydroxypyridin-4-one (CP41) and 1-(2'-hydroxyethyl)-2-ethyl-3-hydroxypyridin-4-one (CP102), are orally active iron chelators and ester prodrugs of these molecules are currently under investigation. A liquid extraction method using acetonitrile and 2-propanol (80:20 v/v) under acidic and NaCl-saturated conditions has been developed in order to efficiently extract these HPOs from various matrices. The extracted HPOs were determined using a reversed phase polymer HPLC column (PLRP-S 100 A) and the gradient ion-pair mobile phase containing tetrabutylammonium chloride (5 mM) and EDTA (0.5 mM). The extraction recovery of these chelators in phosphate buffer, rat blood and liver homogenate varied from 85 to 94%. The coefficients of variation (C.V.) for within-day determination were in the range of 1.4-3.3% at 1 mM and 2.0-4.7% at 0.1 mM. High accuracy of determination was also achieved.

Synthesis, physicochemical characterization, and biological evaluation of 2-(1'-hydroxyalkyl)-3-hydroxypyridin-4-ones: novel iron chelators with enhanced pFe(3+) values

The synthesis of a range of 2-(1'-hydroxyalkyl)-3-hydroxypyridin-4-ones as bidentate iron(III) chelators with potential for oral administration is described. The pK(a) values of the ligands and the stability constants of their iron(III) complexes have been determined. Results indicate that the introduction of a 1'-hydroxyalkyl group at the 2-position leads to a significant improvement in the pFe(3+) values. Such an effect was found to be greater with the hydroxyethyl substituent than with the hydroxymethyl substituent, particularly in the cases of 1-ethyl-2-(1'-hydroxyethyl)-3-hydroxypyridin-4-one (pFe(3+) = 21.4) and 1,6-dimethyl-2-(1'-hydroxyethyl)-3-hydroxypyridin-4-one (pFe(3+) = 21.5) where an enhancement on pFe(3+) values in the region of two orders of magnitude is observed, as compared with Deferiprone (1, 2-dimethyl-3-hydroxypyridin-4-one) (pFe(3+) = 19.4). The ability of these novel 3-hydroxypyridin-4-ones to facilitate the iron excretion in bile was investigated using a [(59)Fe]ferritin-loaded rat model. Chelators and prodrug chelators possessing high pFe(3+) values show great promise in their ability to remove iron under in vivo conditions.

Gradient ion-pair high-performance liquid chromatographic method for analysis of 3-hydroxypyridin-4-one iron chelators

A gradient ion-pair HPLC separation of highly hydrophilic 3-hydroxypyridin-4-one (HPO) iron chelators is described. The separation of HPOs was performed using a reversed-phase polymer HPLC column (PLRP-S 100 A, 15x0.46 cm ID, 5 microm). The ion-pair buffer contained 1-heptanesulfonic acid (sodium salt) (5 mM) and the pH was adjusted to 2.0 using HCl. The gradient was 2%-35% CH3CN in 20 min and post-run was followed for 5 min using 2% CH3CN and 98% buffer. The flow-rate was 1 ml/min and the analytes were monitored at 280 nm. The retention times of 30 hydrophilic HPOs fell in the range of 10-18 min with sharp peak shapes, although these iron chelators possess various functional groups and distribution coefficients. The application of this HPLC method in the analysis of HPO chelators and their metabolites in rat bile and urine is described.

[The influence of the 20 kDa protein from Bacillus thuringiensis subsp. israelensis on the cytolytic activity of CytA]

In order to understand the influence of the 20 kDa protein on the cytolytic activity of CytA protein, a set of PCR primers were designed to amplify 20 kDa protein and CytA protein genes. The genes were ligated to E. coli expression vector pUHE24 and transformed into E. coli XL1 and DH5 alpha. The clones, LZ20, LZcytA and LZ20A containing 20 kDa protein gene, cytA protein gene and 20 kDa-cytA genes were obtained respectively. The influence of the clones on the growth of E. coli cells was determined under induction of IPTG. The results showed that the growth of LZ20 cells were not affected, LZcytA cells were killed, and the growth of LZ20A cells were not affected. It was suggested that expression product of 20 kDa protein gene protected the host cells from the cytolytic effect of CytA protein. This was supported by using different host strains.

Investigation into the correlation between the structure of hydroxypyridinones and blood-brain barrier permeability

Bidentate hydroxypyridinones are under active development as orally active iron chelators. With applications for the treatment of general body iron overload, for instance with thalassaemia, the distribution of the chelators should be limited to peripheral tissue and they should not enter the central nervous system. This study compares the predictive abilities of LogPoctanol and LogPcyclohexane and reports the existence of good correlations between blood-brain barrier (BBB) permeability and both values for N-alkylpyridinones. 1,omega-Hydroxyalkyl hydroxypyridinones penetrate the BBB much more slowly than the simple 1-alkyl derivatives. This observation is likely to have important toxicological implications.

Synthesis, physicochemical properties and biological evaluation of aromatic ester prodrugs of 1-(2'-hydroxyethyl)-2-ethyl-3-hydroxypyridin-4-one (CP102): orally active iron chelators with clinical potential

The synthesis of seven aromatic ester derivatives of 1-(2'-hydroxyethyl)-2-ethyl-3-hydroxypyridin-4-one is described. These ester prodrugs have been designed to target iron chelators to the liver, the major iron storage organ. In principle this should improve chelation efficacy and minimize toxicity. The distribution coefficients of these ester prodrugs between 1-octanol and MOPS buffer pH 7.4 were measured together with their rates of hydrolysis at pH 2 and pH 7.4, in rat blood and liver homogenate. Esters with heteroaromatic acid moieties were found to be less stable than benzoyl analogues. The in-vivo iron mobilisation efficacy of these ester prodrugs has been compared with that of the parent drug using a 59Fe-ferritin loaded rat model. Many prodrugs were found to enhance the ability of the parent hydroxypyridinone to facilitate 59Fe excretion. However, not all prodrugs provided increased efficacy, demonstrating that lipophilicity is not the only factor which influences drug efficacy. Furthermore, no clear correlation between efficacy and susceptibility to hydrolysis was detected. The picolinic and nicotinic ester derivatives appear to offer the best potential as prodrugs as they have a relatively low LogP value and yet lead to enhanced efficacy over the parent hydroxypyridinone.

In vivo iron mobilisation evaluation of hydroxypyridinones in 59Fe-ferritin-loaded rat model

Although there are a number of well-characterised animal models available for testing and comparing the efficacy of iron chelators, most are expensive to operate and are not capable of providing rapid and reproducible results. The method described herein is based on the labelling of rat liver with 59Fe using rat 59Fe-ferritin. This method produces highly reproducible data of the type necessary for dose-response investigations, comparison of the efficacies of different administration routes, and structure activity studies.

Metabolism of 9-(2-chlorobenzyl)-, 9-(2-methylbenzyl)- and 9-(2-methoxybenzyl)-adenines by hamster hepatic microsomes

It was previously found that 9-benzyladenine (BA) was extensively N1-oxidised by animal hepatic microsomes; further, mononitrosubstitution in the phenyl moiety of BA significantly modified the N1-oxidation rates of the corresponding substrates. In order to establish whether the electronic nature or a steric effect of the substituents in the phenyl moiety is the reason for the modification of N1-oxidation rate, the metabolism of some 2'-substituted 9-benzyladenines, i.e. 9-(2-chlorobenzyl)adenine (2CBA), 9-(2-methyl-benzyl)adenine (2MBA) and 9-(2-methoxybenzyl)adenine (2MOBA), by hamster hepatic microsomes was studied. It was found that the N1-oxide was still the major metabolite for 2CBA. However, only minor amounts of N1-oxides were formed during microsomal incubation with 2MBA and 2MOBA. On the other hand, in spite of the higher N1-oxidation rate of 2CBA, its total biotransformation rate was slightly lower than the other two substrates. Like other 9-aralkyladenines previously studied, dealkylation occurred for all three substrates. It was also found that another two metabolites formed in significant amounts in the incubates from both 2MBA and 2MOBA. These metabolites were not fully characterised and their structures unknown.

Surgical treatment of cervical spine tumors

Of 40 patients with cervical spine tumor treated from 1980 to 1990, 24 had a primary tumor and 16 a metastatic tumor. Thirty-four patients were operated on through anterior and 5 through posterior approach. Preoperative neck pain was relieved and muscular strength of shoulder and arm increased after operation. Total excision methylmethacrylate or metal prosthesis replacement was used. Total excision of the lesion was emphasized for preventing the recurrence of the tumor. Indications and aims of the operation are discussed.

High efficient transfer and expression of human clotting factor IX cDNA in cultured human primary skin fibroblasts from hemophilia B patient by retroviral vectors

To study the possibility of somatic gene therapy for hemophilia B via gene transfer to primary factor IX-deficient skin fibroblasts, we constructed four retroviral vectors containing factor IX cDNA driven by retroviral LTR promoter, SV40 early promoter and mouse MT-I promoter, respectively. These retroviral vectors were transfected into an amphotropic packaging cell line, PA317 cells, by electroporation, and a human fibrosarcoma cell line, HT1080 cells, was used to assay the factor IX-virus titers of these four virus-producing PA317 cells, which ranged from 2 x 10(4) to 5 x 10(5) cfu/ml. The factor IX proteins produced by bulk population of four virus-producing PA317 cells were determined by ELISA. Results showed that LTR promoter directed the highest production of factor IX at the rate of 584 ng/10(6) cells/24 h, while SV40 early promoter and MT promoter directed about 10 and 20 times less production of factor IX than LTR promoter. The highest expressed retroviral vector XL-IX was used to infect a line of factor IX-deficient human primary skin fibroblasts, FDIX cells. The factor IX secretion rate of the infected FDIX cells was about 549 ng/10(6) cells/24 h and over 75% of secreted factor IX was biologically active. We are convinced that this factor IX-deficient human primary skin fibroblast had been cured, or genetically corrected, by retroviral-mediated gene therapy in vitro.

Comparative efficacy of levo-praziquantel and praziquantel in treatment of schistosomiasis japonica at a single dose

The result of a randomized double blind comparison of therapeutic efficacy of single doses of levo-praziquantel (L-PZQ) and praziquantel (PZQ) in the treatment of 139 matched pairs of proved cases of schistosomiasis japonica was reported, 268 were chronic early cases and 10 were late cases. The dosage of L-PQZ was 20 mg/kg, and that of PZQ was 40 mg/kg. Four and 6 months after treatment the stool-ova negative conversion rates were 94.8% and 96.3% for the L-PZQ group, and 97.1% and 94.0% for the PZQ group respectively (P greater than 0.05).

Identification of partial mutational sites in human mitochondrial DNA in the Chinese and its significance

A simple method for the identification of mutational sites in human mitochondrial DNA (mtDNA) was described. It was based on the human Cambridge sequence as a relative standard sequence and a single base pair substitution in mtDNA as a unique mutational form. The partial mutational sites can be determined using this method which was characterized by combining the restriction mapping with the analysis for the table of human mtDNA potential mutational sites with rapidity and simplicity. In the meanwhile, six mtDNA mutational sites found in Chinese population were identified by means of this method.

Mitochondrial DNA polymorphism in Chinese

Human mitochondrial DNA (mtDNA) restriction endonuclease fragment patterns were analyzed using placenta DNA isolated from 273 individuals representing four different nationalities, the Han, the Uygur, the Kazakh and the Hui populations. Thirty-eight fragment patterns (morphs) were observed with the enzyme ApaI, BamHI, EcoRI, HindIII, HinfI, HhaI, HapII, KpnI, Mbol, PstI, PvuII, SacI, ScaL and XhoI. Fourteen new morphs, including some only existing in individual racial and national populations were observed, which indicates that there is a significant difference in the distribution of mtDNA morphs among various national and racial populations. By comparison with the mtDNA sequences in primate species, some mtDNA ancestral morphs were found to be retained in Oriental population today. This result provided indirect evidence that Asia may be one of the human original sources. Genetic distances among four national populations computed and employed in construction of an average linkage tree suggested that the Uygur and the Kazakh populations combined to form a branch at first, then the Han and the Hui came together to form another one, and at last, these two branches converged into a stem. Again, it was found that the internal variation within the Uygur and the Kazakh populations was greater than that within the Han and the Hui populations. These results showed a relationship among the four different national populations in China based on the molecular level.

The distribution of P elements in D. melanogaster along the coast of China studied by DNA hybridization method

The distribution of the P-M system in four local Drosophila melanogaster populations obtained in southern China has been examined by mating tests. There was no P strain. A HindIII fragment of the P element has been cloned, named as pPH 0.86, and used as probe in this study. The distribution of the P element itself in thirteen local D. melanogaster populations along the eastern coast of China has been studied by the method of DNA hybridization. It is found that all the populations obtained from the north of Shanghai carry P elements but few populations from the south of Shanghai carry P elements. In comparison with the mating test, the method of DNA hybridization is more direct and reliable. The origin and trends of distribution of P elements in China are discussed in this paper.