Effects of sevoflurane exposure during different stages of pregnancy on the brain development of rat offspring.

OBJECTIVE: This study explored the effects of sevoflurane exposure during different stages of pregnancy on the brain development of offspring. METHODS: Thirty-six pregnant SD rats were randomly divided into 4 groups: control, sevoflurane exposure in early (S1) pregnancy, sevoflurane exposure in middle (S2) pregnancy, and sevoflurane exposure in late (S3) pregnancy. After natural birth, the learning and memory capacity of offspring rats was analyzed using the Morris water maze experiment. The hippocampi of offspring rats were collected. The levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in the hippocampus were measured by ELISA. Additionally, the Nissl bodies in the hippocampus were analyzed using Nissl staining. Immunohistochemistry was used to examine the expression of BDNF and CPEB2 in the hippocampus of offspring. Proteins related to the NR4A1/NF-κB pathway were analyzed using western blotting. RESULTS: The memory and learning capacity of offspring rats was significantly reduced in the S1 and S2 groups compared to the control group (p < 0.05), while there was no obvious difference between the control and S3 groups (p > 0.05). The level of IL-1ß was significantly increased (p < 0.05) in the S1 group compared with the control group. Sevoflurane anesthesia received in early and middle pregnancy could significantly affect the formation of Nissl bodies in the hippocampi of offspring rats. In addition, the expression of BDNF and CPEB2 in the hippocampi of offspring rats was greatly decreased in the S1 group compared with the control group (p < 0.05). The expression of NR4A1 in the hippocampi of rat offspring was significantly decreased in the S1 and S2 groups compared with the control group (p < 0.05). The expression of proteins related to the NF-κB pathway was increased in the S1 group compared to the control group (p < 0.05). CONCLUSIONS: The neurotoxic effect of maternal sevoflurane anesthesia on the brain development of offspring is higher when the exposure occurs in early pregnancy than in late pregnancy, and its mechanism might involve the NR4A1/NF-κB pathway to increase the secretion of inflammatory cytokines.

Protective Effects of Salidroside against Carbon Tetrachloride (CCl4)-Induced Liver Injury by Initiating Mitochondria to Resist Oxidative Stress in Mice.

The antioxidant effect of salidroside has been proven, but its role in liver injury is poorly understood. In this study, we aimed to evaluate the protective effects and mechanism of salidroside on liver injury induced by carbon tetrachloride (CCl4) in vivo. Mice were pretreated with salidroside (60 mg/kg, intraperitoneally injected, i.p.) once per day for 14 consecutive days and then administered with CCl4 (15.95 g/kg, i.p.) for 24 h to produce a liver injury model. Salidroside attenuated hepatic transaminase elevation in serum and ameliorated liver steatosis and necrosis, thereby suggesting its protective effect on the liver. Salidroside antagonized CCl4-induced toxicity by equilibrating antioxidation system, thereby inhibiting reactive oxygen species accumulation, and restoring mitochondrial structure and function. Salidroside exerts antioxidant and liver-protective effects by selectively inhibiting the activation of genes, including growth arrest and DNA -damage-inducible 45 α (Gadd45a), mitogen-activated protein kinase 7 (Mapk7), and related RAS viral oncogene homolog 2 (Rras2), which induce oxidative stress in the mitogen-activated protein kinase pathway. These results revealed that salidroside can protect the liver from CCl4-induced injury by resisting oxidative stress and protecting mitochondrial function.

Genetic effects of polymorphisms in myogenic regulatory factors on chicken muscle fiber traits.

The myogenic regulatory factors is a family of transcription factors that play a key role in the development of skeletal muscle fibers, which are the main factors to affect the meat taste and texture. In the present study, we performed candidate gene analysis to identify single-nucleotide polymorphisms in the MyoD, Myf5, MyoG, and Mrf4 genes using polymerase chain reaction-single strand conformation polymorphism in 360 Erlang Mountain Chickens from three different housing systems (cage, pen, and free-range). The general linear model procedure was used to estimate the statistical significance of association between combined genotypes and muscle fiber traits of chickens. Two polymorphisms (g.39928301T>G and g.11579368C>T) were detected in the Mrf4 and MyoD gene, respectively. The diameters of thigh and pectoralis muscle fibers were higher in birds with the combined genotypes of GG-TT and TT-CT (p<0.05). Moreover, the interaction between housing system and combined genotypes has no significant effect on the traits of muscle fiber (p>0.05). Our findings suggest that the combined genotypes of TT-CT and GG-TT might be advantageous for muscle fiber traits, and could be the potential genetic markers for breeding program in Erlang Mountain Chickens.

Transition and stability of copolymer adsorption morphologies on the surface of carbon nanotubes and implications on their dispersion.

In this study, the adsorption morphologies as well as stability and transitions of a commercial dispersant copolymer (BYK 9076) on the surface of multiwalled carbon nanotubes (MWCNTs) were studied using Fourier transform infrared and UV-vis spectroscopy, dynamic light scattering, and electron microscopy techniques. The results show that the dispersion of carbon nanotubes in ethanol does not increase continuously with increasing copolymer/CNT ratio, which is correlated with the adsorption morphologies of the copolymer on the CNT surface. At a ratio of copolymer/CNT below 0.5, the morphology is random, shifting to a hemimicelle structure at a ratio from 0.5 to 1.0 while at ratios above 1.0, a cylindrical pattern is seen. The hemimicelle morphology is able to prevent the agglomeration of CNTs when the CNT concentration increases to 8.7 mg/mL, while cylindrical morphology is more efficient and stable to provide dispersion of CNTs at higher concentrations of CNTs.

Identification of SNPs in Cellular Retinol Binding Protein 1 and Cellular Retinol Binding Protein 3 Genes and Their Associations with Laying Performance Traits in Erlang Mountainous Chicken.

CRBP1 (cellular retinol binding protein 1) and CRBP3 (cellular retinol binding protein 3), are important components of the retinoid signaling pathway and take part in vitamin A absorption, transport and metabolism. Based on the role of vitamin A in chicken laying performance, we investigated the polymorphism of CRBP1 and CRBP3 genes in 349 chickens using single strand conformation polymorphism and DNA sequencing methods. Only one polymorphism was identified in the third intron of CRBP1, two polymorphisms were detected in CRBP3; they were located in the second intron and the third intron respectively. The association studies between these three SNPs and laying performance traits were performed in Erlang mountainous chicken. Notably, the SNP g.14604G>T of CRBP1 was shown to be significantly associated with body weight at first egg (BWFE), age at first egg (AFE), weight at first egg (WFE) and total number of eggs with 300 age (EN). The CRBP3 polymorphism g.934C>G was associated with AFE, and the g.1324A>G was associated with AFE and BWFE, but none of these polymorphisms were associated with egg quality traits. Haplotype combinations constructed on these two SNPs of CRBP3 gene were associated with BWFE and AFE. In particular, diplotype H2H2 had positive effect on AFE, BWFE, EN, and average egg-laying interval. We herein describe for the first time basic research on the polymorphism of chicken CRBP1 and CRBP3 genes that is predictive of genetic potential for laying performance in chicken.

The regulation of intestinal flora on host's genes may play an essential role in the development of endometrial hyperplastic processes in yang deficiency individuals.

Yang-deficiency constitution (YADC) is linked to a higher vulnerability to various diseases, such as cold coagulation and blood stasis (CCBS) syndrome and infertility. Endometrial hyperplastic processes (EHPs) are a leading cause of infertility in women and are characterized by CCBS. However, it remains unclear whether YADC is related to the development of EHPs. METHODS: We recruited 202 EHPs patients including 147 with YADC (YEH group) and 55 with non-YADC (NYEH group). Fecal samples were collected from 8 YEH patients and 3 NYEH patients and analyzed using 16S rRNA V3-V4 sequencing for gut microbiota analysis. We obtained constitution survey data and a differential gut microbiota dataset from the literature for further analysis. Bioinformatics analysis was conducted using gut microbiota-related genes from public databases. RESULTS: YADC was significantly more prevalent in EHPs than non-YADC (P < 0.001), suggesting it as a potential risk factor for EHPs occurrence (ORpopulation survey = 13.471; ORhealthy women = 5.173). The YEH group had higher levels of inflammation, estrogen, and tamoxifen-related flora compared to NYEH and healthy YADC groups. There was an interaction between inflammation, estrogen, differential flora, and EHPs-related genes, particularly the TNF gene (related to inflammation) and the EGFR gene (related to estrogen), which may play a crucial role in EHPs development. CONCLUSION: YEH individuals exhibit significant changes in their gut microbiota compared to NYEH and healthy YADC. The interaction between specific microbiota and host genes is believed to play a critical role in the progression of EHPs.

Dietary lysine affects chickens from local Chinese pure lines and their reciprocal crosses.

The objective of this experiment was to evaluate the effect of dietary lysine concentration on meat quality and carcass traits in 2 chicken lines, SD02 and SD03, and their crosses, both originating from a Chinese native breed, the Erlang Mountainous chicken. The lines were selected for 4 generations by Sichuan Agricultural University (Ya'an, China); for the present study, chickens from the 2 lines and their crosses were randomly assigned at hatch to 1 of 2 dietary groups. One group was offered diets containing 1, 0.85, and 0.70% total lysine, whereas the other was offered diets with 1.15, 1, and 0.85% total lysine from d 1 to 28, d 29 to 49, and d 50 to 70, respectively. In total, 252 chickens were commercially processed at 70 d old. Traits measured included live BW, subcutaneous fat thickness, weight of carcass, eviscerated carcass, semi-eviscerated carcass, breast muscle (left pectoralis major and minor), leg muscle (boneless left drum plus thigh), heart, gizzard, proventriculus, spleen, liver, comb, and abdominal fat, color parameters lightness, redness, or yellowness (L*, a*, and b*), pH, and breast muscle intramuscular fat content. The results indicated that, although dietary lysine concentration did not affect subcutaneous fat thickness, color parameters, pH, intramuscular fat content, and organ weights, there were effects on feed conversion and muscle and BW (P < 0.05). Males and females displayed major differences in feed conversion, BW, muscle growth, and organ weight. The Line SD02 chickens grew faster and displayed less fat deposition and superior feed conversion compared with Line SD03 and the reciprocal crosses. In conclusion, performance of the chicken stocks evaluated in this study differs substantially in muscle weight and carcass weight.

MUSTN1 mRNA Abundance and Protein Localization is Greatest in Muscle Tissues of Chinese Meat-Quality Chickens.

The Mustang, Musculoskeletal Temporally Activated Novel-1 Gene (MUSTN1) plays an important role in regulating musculoskeletal development in mammals. We evaluated the developmental and tissue-specific regulation of MUSTN1 mRNA and protein abundance in Erlang Mountainous (EM) chickens. Results indicated that MUSTN1 mRNA/protein was expressed in most tissues with especially high expression in heart and skeletal muscle. The MUSTN1 protein localized to the nucleus in myocardium and skeletal muscle fibers. There were significant differences in mRNA and protein abundance among tissues, ages and between males and females. In conclusion, MUSTN1 was expressed the greatest in skeletal muscle where it localized to the nucleus. Thus, in chickens MUSTN1 may play a vital role in muscle development.

[Study on RSLC fingerprint of Lycii cortex].

OBJECTIVE: To develope a method of RSLC fingerprint analysis for the quality evaluation of Lycii Cortex, and assess the differences of Lycii Cortex from Lycium chinense and L. barbarum. METHODS: All separations were performed using a Rapid Separation Liquid Chromatography (RSLC) system with an Acquity UPLC C18 (2.1 mm x 100 mm, 1.7 microm) column. The mobile phase was consisted of acetonitrile and 0.1% aqueous acetic acid. The flow rate was 0.3 mL/min using gradient elution. The column temperature was 40 degrees C and detection wavelength was set at 315 nm. Lycii Cortex samples collected from different habitats were assessed by similarity analysis (SA), hierarchical clustering analysis (HCA) and principle component analysis (PCA). RESULTS: The characteristic RSLC fingerprint was established with 14 common peaks. 14 hatches of samples were classified as 2 clusters by HCA and PCA, and the result demonstrated that there were differences in the contents of chemical composition between 2 species of Lycii Cortex. CONCLUSION: The established RSLC fingerprint is specific and the method is rapid, simple and reliable, which can be used to control the quality of Lycii Cortex in the markets.

[Clinical and magnetic resonance imaging features of neuromyelitis optics with positive anti-nuclear antibody serum].

OBJECTIVE: To analyze the clinical features and brain, spinal cord magnetic resonance imaging (MRI) features of neuromyelitis optical (NMO) patients with positive anti-nuclear antibody serum (ANAs). METHODS: The clinical data of expanded disability status scale (EDSS) score, duration of the first relieving phase and first year recurrence-positive rate and MRI features of 34 NMO patients at our hospital during the period of 2006-2011 were retrospectively reviewed and divided into two groups according to the outcome of antibodies test:ANAs positive group (n=14) and ANAs negative group (n=20). RESULTS: (1) In the ANAs-positive group, the EDSS score of first NMO attack was (2.8±1.1), first remission continued to (9±9) months and the first year recurrence-positive rate was 71.0%; in the ANAs-negative group, the EDSS score of first NMO attack was 2.3±0.8, first remission continued to (31±39) months and the first year recurrence-positive rate was 30.0%. The differences in the first attack EDSS score, duration of first remission and first recurrence rate between two groups were statistically significant (P<0.05). (2) Brain damage-positive rate in the ANAs-positive group on prompt MRI was 35.71% (5/14) and it was higher than that in ANAs-negative group (5/20). But no significant difference existed between two groups. The spinal cord lesions were predominantly located in cervical and thoracic spinal cords simultaneously in both groups (about 50% respectively). And, in the ANAs-positive group, the cervical lesions involved were much more common than the thoracic counterparts (6/14 vs 1/14). However, in the ANAs-negative group, thoracic segments were usually involved (6/20 vs 4/20). CONCLUSION: With severe neurological deficits in the first clinical attack and a short remission, ANAs-positive NMO patients are more prone to relapse in the first year, brain damage and cervical cord injury.

Age-related expression profile of the SLC27A1 gene in chicken tissues.

The solute carrier family 27 (SLC27, also known as fatty acid transport proteins [FATPs]) plays important biological roles in cells. However, there is no report about the expression profile of SLC27 member in chicken. In this study, we quantified the expression of SLC27A1 (FATP1) mRNA in a mountainous black-boned chicken breed (MB) and a commercial meat type chicken breed (S01), to discern the tissue and age-related specific expression pattern and their potential involvement in fat deposition and muscle fatty acid metabolism. Real-time quantitative PCR assays were developed for accurate measurement of SLC27A1 mRNA levels in different tissues from chicken with different ages (0-12 weeks). Expression of SLC27A1 mRNA was detected in all tissues examined. There was a significantly age-related change of the SLC27A1 mRNAs in heart, breast muscle (BMW), leg muscle (LMW), liver, and abdominal fat (AF) tissues (P < 0.05). The breast muscle and leg muscle tissues had the highest expression of SLC27A1 mRNA than the other tissues from the same individual at 0, 2 and 4 weeks. The overall SLC27A1 mRNA level exhibited a "rise-decline" developmental change in all tissues except for breast muscle, subcutaneous fat, and brain. The S01 chicken had a higher expression of the SLC27A1 mRNA in breast muscle, subcutaneous fat, and heart tissues than the MB chicken. Our results showed that the expression of SLC27A1 mRNA in chicken tissues exhibits specific developmental changes and age-related patterns.

Electrochemical Investigations of Steels in Seawater Sea Sand Concrete Environments.

Seawater and sea sand concrete (SWSSC) is an environmentally friendly alternative to ordinary Portland cement concrete for civil construction. However, the detrimental effect of high chloride content of SWSSC on the corrosion resistance of steel reinforcement is a concern. This study undertook the electrochemical corrosion behaviour and surface characterizations of a mild steel and two stainless steels (AISI type 304 and 316) in various simulated concrete environments, including the alkaline + chloride environment (i.e., SWSSC). Open circuit potential (OCP), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were employed. Though chloride is detrimental to the corrosion resistance of mild steels, a simultaneous presence of high alkalinity in SWSSC negate the detrimental effect of chloride. In the case of stainless steels, a high level of alkalinity is found to be detrimental, whereas chloride seems to have less detrimental effect on their corrosion resistance.

Bonded CFRP/Steel Systems, Remedies of Bond Degradation and Behaviour of CFRP Repaired Steel: An Overview.

This literature review has examined the use of FRP composite materials as a potential retrofitting technique for civil structures. Importantly, the various material properties, bond mechanisms, durability issues and fatigue resistance have been discussed. Studies exploring the performance of CFRP repaired steel have strongly indicated its potential as a rehabilitation material. These systems offer many improvements over the current bulky and less chemically resistant methods of bolting or welding steel plate patches. This review has established and highlighted the factors that affect CFRP/steel bond durability, namely surface preparation, curing, corrosion, fatigue loading, temperature and moisture ingress through studies that focus on their effect. These studies, however, often focus on a single influencing factor or design criteria. Only limited studies have investigated multiple parameters applied simultaneously, even though they commonly occur together in industrial practice. This review aimed to summarise the numerous influencing parameters to give a clearer understanding of the relevance of CFRP repaired steel structures.

Association of FATP1 gene polymorphisms with chicken carcass traits in Chinese meat-type quality chicken populations.

In this study, we aimed to detect the single nucleotide polymorphisms (SNPs) of the chicken FATP1 gene and discern the potential association between FATP1 SNPs and chicken carcass traits. A total of 620 meat-type quality chickens from six commercial pure lines (S01, S02, S03, S05, S06 and D99) and two cross lines (S05 × S01 and S06 × S01) were screened by using the single-strand conformational polymorphism analysis (SSCP) and DNA sequencing. Five SNPs [g.49360G > A, g.48195G > A, g.46847A > G, g.46818A > G, and g.46555A > G] were identified in chicken FATP1 gene. SNP g.46818 A > G was a rare variant and was not considered in the subsequent analysis. Sixteen haplotypes were reconstructed on the basis of the other four SNPs. The linear regression model analysis indicated that there were significant associations of certain diplotypes with part of carcass traits, such as live weight (LW), carcass weight (CW), and semi-eviscerated weight (SEW) (P < 0.05). In particular, diplotype H2H4 had a negative effect on LW, CW, SEW, and abdominal fat weight (AW); diplotype H6H10 had the highest reducing effect on subcutaneous fat thickness (SFT). Our results suggested that FATP1 gene polymorphisms were associated with chicken carcass traits or was linked with the major gene. The SNPs in this gene may be utilized as potential markers for marker-assisted selection (MAS) during chicken breeding.

Effect of Fibers Configuration and Thickness on Tensile Behavior of GFRP Laminates Exposed to Harsh Environment.

The present study indicates the importance of using glass fiber reinforced polymer (GFRP) laminates with appropriate thickness and fibers orientation when exposed to harsh environmental conditions. The effect of different environmental conditions on tensile properties of different GFRP laminates is investigated. Laminates were exposed to three environmental conditions: (1) Freeze/thaw cycles without the presence of moisture, (2) freeze/thaw cycles with the presence of moisture and (3) UV radiation and water vapor condensation cycles. The effect of fiber configuration and laminate thickness were investigated by considering three types of fiber arrangement: (1) Continuous unidirectional, (2) continuous woven and (3) chopped strand mat and two thicknesses (2 and 5 mm). Microstructure and tensile properties of the laminates after exposure to different periods of conditioning (0, 750, 1250 and 2000 h) were studied using SEM and tensile tests. Statistical analyses were used to quantify the obtained results and propose prediction models. The results showed that the condition comprising UV radiation and moisture condition was the most aggressive, while dry freeze/thaw environment was the least. Furthermore, the laminates with chopped strand mat and continuous unidirectional fibers respectively experienced the highest and the lowest reductions properties in all environmental conditions. The maximum reductions in tensile strength for chopped strand mat laminates were about 7%, 32%, and 42% in the dry freeze/thaw, wet freeze/thaw and UV with moisture environments, respectively. The corresponding decreases in the tensile strength for unidirectional laminates were negligible, 17% and 23%, whereas those for the woven laminates were and 7%, 24%, and 34%.

Prestressed Unbonded Reinforcement System with Multiple CFRP Plates for Fatigue Strengthening of Steel Members.

Carbon fiber reinforced polymer (CFRP) composites have exhibited a great potential for strengthening of steel structures. In the current study, an innovative prestressed unbonded reinforcement (PUR) system is introduced for fatigue strengthening of existing steel members. The system relies on a pair of mechanical clamps; each holds multiple CFRP plates and anchors their prestressing forces to the steel substrate via friction. A finite element model was established to optimize the design of the required mechanical components of the system. A set of static and fatigue tests was conducted on the developed mechanical clamps as the key elements of the proposed PUR system. The performance of the PUR system was then evaluated using a set of fatigue tests on two precracked steel plate specimens, one without any strengthening system and the other one strengthened with the proposed PUR system. In the latter specimen, the CFRP plates were prestressed up to about 800 MPa (approximately 30% of the CFRP tensile strength), which resulted in a complete fatigue crack arrest in the precracked steel plate. Furthermore, neither slippage of the mechanical clamps nor any prestress loss in the CFRP plates was observed after 7.5 million fatigue cycles. Based on the promising experimental results, obtained from the sets of fatigue tests performed in the current study, it can be concluded that the proposed PUR system can be considered as an efficient alternative to the conventional bonded reinforcement solutions for fatigue strengthening of damaged steel members.

[Association between single nucleotide polymorphism of ADFP gene and carcass traits and intramuscular fat content in chicken].

In order to investigate the effect of ADFP gene on the carcass traits and intramuscular fat content of Da-heng high-quality chicken, we analyzed the coding sequence of the ADFP gene by single-strand conformation polymorphism (SSCP) and DNA sequencing in five pure lines and three crossbreds. We found three single nucleotide polymorphism sites, including A/T at base position 4,079 (locus A), C/T at base position 4,843 (locus B) and A/G at base position 7,070 (locus C). GLM analysis for the effect of genotypes on carcass traits and intramuscular fat content demonstrated a significant effect on leg muscle percentage, abdomen fat weight, abdominal fat percentage and intra-muscular fat content in locus A (P < 0.05), a significant association with living body weight and carcass weight for locus B (P < 0.05) and a significant association with breast muscle weight and intramuscular fat content (P < 0.05), and a very significant association with breast muscle percentage for locus C (P < 0.01). It was concluded that ADFP gene may be a major gene or linked to such a gene that affects the fat traits of birds. Polymorphic loci A and C could be used as molecular markers for abdominal fat weight, abdominal fat percentage and intramuscular fat content in birds in future studies.

[Freeze-drying of oleanolic acid-loaded nanosuspensions].

OBJECTIVE: Several cryoprotectants were employed to study the protective effect on the freeze-drying process of the oleanolic acid-loaded nanosuspensions (OLA-LS) in order to select the optimum formulation. METHOD: The protective effect was evaluated by measuring the mean particle size of samples before and after freeze-drying process. RESULT: Sucrose with the concentration of 10% was selected as the optimum cryoprotectant. The average size of excellent sample was 236.3 nm (versus 211.2 nm of fresh one), and a much higher polydispersity index of 0.242 (versus 0.180). CONCLUSION: The optimum lyophilized powder could be obtained with suitable type of cryoprotectant with appropriate concentration and proper freeze-drying conditions.

Effects of zinc on the induction of metallothionein isoforms in hippocampus in stress rats.

Metallothioneins (MTs) are involved in the cellular metabolism of zinc and in cytoprotection against stress factors. Hippocampus plays a specific role in the body's response to stressors. The present study was conducted to evaluate the effects of zinc on the expression of metallothionein isoforms in the hippocampus of stress rats. The animal model of psychologic stress was developed by restraint for 4 weeks. Wistar rats were randomly assigned to 6 groups: control group, zinc-deficient group, zinc-supplemented group, and the corresponding 3 stress groups. Three separate diets of different zinc contents (1.73 ppm, 17.7 ppm, and 41.4 ppm, respectively) were used in this study. Compared with the control group, the stress groups had higher inductions of MTs and MT-1 and MT-3 mRNA in hippocampus. On the one hand, the expressions of MTs and their mRNAs in hippocampus were downregulated in the zinc-deficient group; however, their expressions were evidently enhanced in the stress zinc-deficient group. MT induction in the zinc-supplemented group was increased. Furthermore, the stress zinc-supplemented group had a more significant yield of MTs and their mRNAs. In addition, the levels of plasma cortisol, interleukin-6 (IL-6), IL-1, and nitric oxide (NO) were increased clearly in the zinc-deficient group and the stress groups. The results suggest that zinc deficiency may decrease and zinc supplementation may increase the expressions of MTs and their mRNAs in hippocampus; moreover, stress can increase their expressions dramatically. The impairment of stress on the body may be involved with the nutrition status of zinc, and zinc deficiency can lower the body's adaptability to stress.

[Transpositional behaviour analysis of Ds element from different insertion sites on chromosome 4 in rice].

Transgenic plants with Ds element distributed over different loci on chromosome 4 (Fig. 1) and the homozygous transformants with Ac transposase gene were established through Agrobacterium-mediated approach. In this study, the plants carrying Ds element from different loci were crossed with the plant carrying Ac transposase individually. The plants of F(1) generation carrying both Ds element and Ac transposase were used to produce the F(2) populations (Table 1). Analysis of the F(2) generation by the PCR method revealed that the excision frequencies of Ds element were higher in the telomeric region of chromosome 4 than in the centromeric region (Fig. 4). These results showed that the insertion site of Ds element has strong effect on its excision frequency. We suggest that the special construct of chromosome near the insertion site of Ds element is related to the excision frequency of the Ds element.