TCP3 interacts with R2R3-MYB proteins, promotes flavonoid biosynthesis and negatively regulates the auxin response in Arabidopsis thaliana.

TCP proteins belong to the plant-specific bHLH transcription factor family, and function as key regulators of diverse developmental processes. Functional redundancy amongst family members and post-transcriptional down-regulation by miRJAW of several TCP genes complicate their functional characterization. Here, we explore the role of TCP3 by analyzing transgenic plants expressing miRJAW-resistant mTCP3 and dominant-negative TCP3SRDX. Seedlings and seeds of mTCP3 plants were found to hyper-accumulate flavonols, anthocyanins and proanthocyanidins, whereas levels of proanthocyanidins were slightly reduced in TCP3SRDX plants. R2R3-MYB proteins control not only early flavonoid biosynthetic steps but also activate late flavonoid biosynthetic genes by forming ternary R2R3-MYB/bHLH/WD40 (MBW) complexes. TCP3 interacted in yeast with R2R3-MYB proteins, which was further confirmed in planta using BiFC experiments. Yeast three-hybrid assays revealed that TCP3 significantly strengthened the transcriptional activation capacity of R2R3-MYBs bound by the bHLH protein TT8. Transcriptome analysis of mTCP3 and TCP3SRDX plants supported a role for TCP3 in enhancing flavonoid biosynthesis. Moreover, several auxin-related developmental abnormalities were observed in mTCP3 plants. Transcriptome data coupled with studies of an auxin response reporter and auxin efflux carriers showed that TCP3 negatively modulates the auxin response, probably by compromising auxin transport capacity. Genetic experiments revealed that the chalcone synthase mutant tt4-11 lacking flavonoid biosynthesis abrogated the auxin-related defects caused by mTCP3. Together, these data suggest that TCP3 interactions with R2R3-MYBs lead to enhanced flavonoid production, which further negatively modulates the auxin response.

Comprehensive evaluation of urban river ecological bank protection based on AHP-TOPSIS method.

An ecological revetment is a new type that combines natural vegetation with civil engineering technology to establish functions, such as flood control, drainage, ecology, and landscape. Various types of ecological and other bank protection lead to different bank protection effects. Urban river ecological bank protection can effectively prevent bank collapse and promote mutual infiltration between river water and soil and is important for maintaining the balance of the river ecosystem and enhancing the ecological service function of river bank protection. To scientifically and accurately evaluate the ecological protection of riverbanks, this study screened 16 evaluation indicators based on four aspects: structural stability, ecological functionality, landscape suitability, and socio-economic status. A comprehensive evaluation index system for urban river ecological protection was constructed and an urban river ecological protection evaluation model based on the AHP - TOPSIS method was established. The model was used to evaluate the ecological protection of the rivers in the study area. The results revealed that the evaluation value, 0.830, of the self-embedded retaining wall exhibited the best performance among the current slope protection types. In addition, structural stability is a crucial factor in river ecological revetments, and the evaluation results were consistent with the revetment type selected in actual engineering. Therefore, the evaluation system constructed in this study is reasonable and reliable and has strong generalizability. This study provides theoretical guidance for selecting ecological protection banks for future river management projects and has specific references important for academic research and the development of environmental protection banks.

Nitrogen use efficiency in grain production and the estimated nitrogen input/output balance in China agriculture.

BACKGROUND: Understanding the nitrogen (N) use efficiency and N input/output balance in the agricultural system is crucial for best management of N fertilisers in China. RESULTS: In the last 60 years, N fertiliser consumption correlated positively with grain production. During that period the partial factor productivity of N (PFPN ) declined greatly from more than 1000 kg grain kg⁻¹ N in the 1950s to nearly 30 kg grain kg⁻¹ N in 2008. This change in PFPN could be largely explained by the increase in N rate. The average agronomic efficiency of fertiliser N (AEN ) for rice, wheat and maize during 2000-2010 was 12.6, 8.3 and 11.5 kg kg⁻¹ respectively, which was similar to that in the early 1980s but lower than that in the early 1960s. Estimation based on statistical data showed that a total of 49.16 × 106 t of N was input into Chinese agriculture, of which chemical N, organic fertiliser N, biological fixed N and other sources accounted for 58.2, 24.3, 10.5 and 7.0% respectively. Nitrogen was surplus in all regions, the total N surplus being 10.6 × 106 t (60.6 kg ha⁻¹). CONCLUSION: The great challenge is to balance the use of current N fertilisers between regions and crops to improve N use efficiency while maintaining or increasing crop production under the high-intensity agricultural system of China.

The ROXY1 C-terminal L**LL motif is essential for the interaction with TGA transcription factors.

Glutaredoxins (GRXs) are small, ubiquitous, glutathione-dependent oxidoreductases that participate in redox-regulated processes associated with stress responses. Recently, GRXs have been shown to exert crucial functions during flower developmental processes. GRXs modulate their target protein activities by the reduction of protein disulfide bonds or deglutathionylation reactions. The Arabidopsis (Arabidopsis thaliana) GRX ROXY1 participates in petal primordia initiation and further petal morphogenesis. ROXY1 belongs to a land plant-specific class of GRXs with a CC-type active site motif, deviating from the ubiquitously occurring CPYC and CGFS GRX classes. ROXY1 was previously shown to interact with floral TGA transcription factors in the nucleus, and this interaction is a prerequisite for ROXY1 to exert its activity required for Arabidopsis petal development. Deletion analysis further identified the importance of the ROXY1 C terminus for the ROXY1/TGA protein interactions and for the ROXY1 function in petal development. Here, by dissecting the ROXY1 C terminus, an α-helical L**LL motif immediately adjacent to the ROXY1 C-terminal eight amino acids was identified that is essential for the interaction with TGA transcription factors and crucial for the ROXY1 function in planta. Similar to the α-helical L**LL motifs binding to transcriptional coactivators with liganded nuclear receptors in animals, a hydrophobic face formed by the conserved leucines in the L**LL motif of ROXY1 possibly mediates the interaction with TGA transcription factors. Thus, the α-helical L**LL sequence is a conserved protein-protein interaction motif in both animals and plants. Furthermore, two separate TGA domains were identified by deletion experiments as being essential for mediating TGA protein interactions with ROXYs.

Arabidopsis basic leucine-zipper transcription factors TGA9 and TGA10 interact with floral glutaredoxins ROXY1 and ROXY2 and are redundantly required for anther development.

ROXY1 and ROXY2 are CC-type floral glutaredoxins with redundant functions in Arabidopsis (Arabidopsis thaliana) anther development. We show here that plants lacking the basic leucine-zipper transcription factors TGA9 and TGA10 have defects in male gametogenesis that are strikingly similar to those in roxy1 roxy2 mutants. In tga9 tga10 mutants, adaxial and abaxial anther lobe development is differentially affected, with early steps in anther development blocked in adaxial lobes and later steps affected in abaxial lobes. Distinct from roxy1 roxy2, microspore development in abaxial anther lobes proceeds to a later stage with the production of inviable pollen grains contained within nondehiscent anthers. Histological analysis shows multiple defects in the anther dehiscence program, including abnormal stability and lignification of the middle layer and defects in septum and stomium function. Compatible with these defects, TGA9 and TGA10 are expressed throughout early anther primordia but resolve to the middle and tapetum layers during meiosis of pollen mother cells. Several lines of evidence suggest that ROXY promotion of anther development is mediated in part by TGA9 and TGA10. First, TGA9 and TGA10 expression overlaps with ROXY1/2 during anther development. Second, TGA9/10 and ROXY1/2 operate downstream of SPOROCYTELESS/NOZZLE, where they positively regulate a common set of genes that contribute to tapetal development. Third, TGA9 and TGA10 directly interact with ROXY proteins in yeast and in plant cell nuclei. These findings suggest that activation of TGA9/10 transcription factors by ROXY-mediated modification of cysteine residues promotes anther development, thus broadening our understanding of how redox-regulated TGA factors function in plants.

Actin depolymerization is sufficient to induce programmed cell death in self-incompatible pollen.

Self-incompatibility (SI) prevents inbreeding through specific recognition and rejection of incompatible pollen. In incompatible Papaver rhoeas pollen, SI triggers a Ca2+ signaling cascade, resulting in the inhibition of tip growth, actin depolymerization, and programmed cell death (PCD). We investigated whether actin dynamics were implicated in regulating PCD. Using the actin-stabilizing and depolymerizing drugs jasplakinolide (Jasp) and latrunculin B, we demonstrate that changes in actin filament levels or dynamics play a functional role in initiating PCD in P. rhoeas pollen, triggering a caspase-3-like activity. Significantly, SI-induced PCD in incompatible pollen was alleviated by pretreatment with Jasp. This represents the first account of a specific causal link between actin polymerization status and initiation of PCD in a plant cell and significantly advances our understanding of the mechanisms involved in SI.

High adsorption capacity of Mg-Al-modified biochar for phosphate and its potential for phosphate interception in soil.

In this study, Mg and/or Al modified biochars (MABC1, MBC2, ABC3) prepared by co-precipitation were to explore their phosphate adsorption capacity from aqueous solution and the potential for soil phosphate interception. The results revealed that MABC composites contained more functional groups than MBC and showed a higher surface area than ABC. The surface of MABC contained dispersed MgAl2O4, Mg(OH)2, AlOOH and Al2O3 crystals that were associated with its enhanced maximum phosphate adsorption capacity (153.40 mg g-1). According to Langmuir model, the maximum adsorption capacity of MABC was 15.91, 1.85, and 93.54 times the capacity of MBC, ABC, and raw biochar (BC4), respectively. The addition of MABC in red soil could significantly slow down the release of soil phosphorus, and MABC also had a stronger phosphate interception capacity (59.89%) than other BCs. In summary, MABC exhibits superior phosphate adsorption and interception capacity, making it ideal for treatment and prevention of phosphorus-polluted water.

Contribution and fate of maize residue-15N and urea-15N as affected by N fertilization regime.

Increasing amounts of crop residues are being returned to croplands. Understanding nitrogen (N) availability in crop residues under various N fertilization regimes is important in optimizing N management. Pot experiments were conducted to investigate the contribution, fate and residual effects of urea and maize residue-N using a 15N isotope technique. Four N regimes were tested: three basal-topdressing ratios of N applied as urea (100-0, 75-25, 50-50) and one basal application of 75% N as urea and 25% N as manure (75U+25M). An average of 31.4% wheat N uptake was derived from urea, 9.2% from maize residue, and 59.5% from the soil in the first season. During the growing stages of wheat, maize residue contributed 0.3-4.8% and 3.1-13.2% to soil mineral and microbial biomass N, respectively, and those originated from urea was 1.0-4.2% and 4.6-16.8%, respectively. Regarding the fate of urea and residue-N after the first season, 35.9% and 16.9% of urea-15N and residue-15N were recovered by wheat, 28.1% and 46.9% remained in the soil, and 36.0% and 36.2% were lost. The contribution of urea to crop N uptake and N recovery efficiency increased, while that of residue-N decreased with increasing proportion of topdressing N. Substituting 25% mineral N with manure decreased the urea-15N loss without negative effects on crop dry matter and N uptake. Residual urea-15N and maize residue-15N from the previous season contributed 3.9% and 3.0% to summer maize N uptake. Additionally, 29.3% of residue-15N remained in the soil after the second season, while only 18.6% of urea-15N remained. Our study suggests that fertilizer and crop residue are actively involved in soil N transformation and plant N nutrition, emphasizing the capacities of organic residues to sustainably supply nutrients. Considering the utilization of both N fertilizer and maize residue, we may suggest a 75-25 split in N fertilizer application, but more appropriate options need to be further assessed under different cropping systems.

A Phytophthora capsici Effector Targets ACD11 Binding Partners that Regulate ROS-Mediated Defense Response in Arabidopsis.

Reactive oxygen species (ROS) play a vital role in plant immune response, but the genes involved in the regulation of ROS are scantily reported. Phytophthora pathogens produce a large number of effectors to promote infection, but the modes of action adopted are largely unknown. Here, we report that RxLR207 could activate ROS-mediated cell death in Nicotiana benthamiana and was essential for virulence of P. capsici. We found that this effector targeted BPA1 (binding partner of ACD11) and four members of BPLs (BPA1-Like proteins) in Arabidopsis, and the bpa1 and bpl mutants had enhanced ROS accumulation and cell death under biotic or abiotic stresses. Furthermore, we showed that BPA1 and several BPLs functioned redundantly in plant immunity to P. capsici. We discovered that BPA1 and all six BPLs interacted with ACD11, and stabilization of ACD11 was impaired in the bpa1, bpl2, bpl3, and bpl4 mutants. RxLR207 could promote the degradation of BPA1, BPL1, BPL2, and BPL4 to disrupt ACD11 stabilization in a 26S proteasome-dependent manner. Taken together, these findings indicate the important roles of Arabidopsis BPA1 and its homologs in ROS homeostasis and defense response, highlighting the usefulness of a pathogen effector-directed approach as a promising strategy for the discovery of novel plant immune regulators.

[Livestock and Poultry Faeces Nitrogen Loading Rate and Its Potential Return to Farmland in China].

To clearly analyze livestock and poultry faeces and the nitrogen loading rate of farmland in different provinces of China and their potential return to agricultural land, the changes of the output of various livestock and poultry faeces in China and the proportion of faeces from all types of livestock and poultry since 1978 were estimated in this paper based on statistical data and literature reviews using the pig manure equivalent (based on nitrogen) and the spatial distribution and pollution risk of livestock and the poultry faeces and nitrogen loading rates. Furthermore, the nitrogen return potential from animal faeces to farmland was analyzed and evaluated for different provinces of China in 2016. The results show that the pig manure equivalent (N) and total N from livestock and poultry faeces in China increases from 1978 to 2005 and is stable from 2005 to 2016. By 2016, the pig manure equivalent (N) and N were 366822.01×104 t and 2024.10×104 t, respectively, reflecting an increase by 105.78%. Approximately 94.03% to 98.34% of the faeces was from poultry, sheep, pigs, and cattle. The livestock and poultry faeces pig manure equivalent (N) and nutrient N were mainly distributed in North-Central China, especially in the Henan Province, accounting for 22.25% and 8.81% of the total in China, respectively, followed by the Sichuan Province. Based on the arable land, planting, and farmland areas, the pig faeces equivalent (N) and its N nutrient per unit area were calculated and the environmental risks were evaluated based on r values. Based on the arable land area, the southwestern and southeastern regions have large loading rates, while the northcentral region has a serious pollution risk of grade Ⅳ. Based on the planting area, the northwestern and southwestern regions have relatively large loading rates, while the northwestern and northcentral regions have pollution risks of grade Ⅲ. Based on the farmland area, the northcentral and southeastern regions have great loading rates and the northcentral region has a pollution risk of grade Ⅲ, Hunan has the largest loading rate, and Beijing, Shandong, and Henan have grade Ⅳ pollution risks. The livestock and poultry faeces pig manure equivalent (N) and amount of N nutrients returning to farmland in China are 113480.75×104 t and 626.15×104 t, respectively, equivalent to 3.07 t·hm-2 and 16.92 kg·hm-2, respectively, and the northcentral region has the largest rates with 8.27 t·hm-2 and 45.62 kg·hm-2, respectively. Based on 50% of the environmental capacity of faeces N, that is, 85 kg·hm-2, the N nutrient return can increase by 2520.21×104 t. The Heilongjiang Province has the greatest potential return, followed by the Sichuan Province.

[Effect of green tea polyphenols on behavioral performances in psychological stress rats].

OBJECTIVE: This study was conducted to explore the effects of green tea polyphenols modulation on changes of behavioral performances in psychological stress rats. METHODS: The animal model of psychological stress was developed by restraint stress for 3 weeks. Wistar rats were randomly assigned to five groups as follows: control group (CT), stress control group (SCT), and three stress groups with low, medium and high-doses of green tea polyphenols modulation respectively (SLG, SMG and SHG). The changes of behavioral performances were examined by open-field test, water maze and step-through test. Serum levels of cortisol, catecholamines, interleukin-6 and interleukin-2 were also detected. RESULTS: The levels of serum cortisol were all increased obviously in the four stress groups. Furthermore, serum cortisol levels in SMG and SHG were decreased than that of SCT. The behavioral performances of SCT rats in open-field test, step-through test and water maze were all changed evidently in contrast to that of CT rats. On the one hand, the changes of behavioral performances in SLG rats were similar to SCT rats. On the other hand, these changes were improved in SMG and SHG rats. In addition, compared with CT group, the levels of plasma IL-6 and IL-1 were increased clearly in the four stress groups, and the contents of serum norepinephrine and dopamine in SCT and SLG groups were decreased dramatically. The serum norepinephrine and dopamine levels in SMG and SHG rats were increased in contrast to that of SCT rats. CONCLUSION: Our results suggested that psychological stress can impair body' s behavioral performances, and moderate green tea polyphenols modulation may improve these abnormal changes.

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.

Cadmium availability and uptake by radish (Raphanus sativus) grown in soils applied with wheat straw or composted pig manure.

Soil cadmium (Cd) availability and uptake by cherry-red radish (Raphanus sativus) grown in Cd-contaminated soils after addition with wheat straw or composted pig manure were studied. The results indicated that wheat straw application promoted radish growth until the second harvest, while pig manure application improved radish biomass in Acid Ferralsols regardless of harvesting seasons. Application with pig manure might be more effective in lowering the Cd uptake by radish than wheat straw. Especially when pig manure of 11.9 g TOC kg(-1) amended into Acid Ferralsols, Cd contents in leaves and roots of radish decreased by 89.2 and 95.7 % at the second harvest, respectively. The changes in Cd fractions distribution in soils after application were contributed to the decline of Cd availability. Furthermore, significantly negative linear correlation (P < 0.05) between the ratio of humic acid (HA) and fulvic acid (FA) in soils and exchangeable Cd was also observed. However, the significantly negative relationship (P < 0.01) between soil pH and exchangeable Cd was merely found in pig manure-treated Acid Ferralsols. The increases in HA/FA ratio or pH values in soils after adding organic materials were also responsible for the decrease of Cd availability in soils and uptake by radish. Thus, it is recommended to stabilize soil Cd and reducing plant uptake by application with composted manure without or slightly contaminated with metals.

[Effects of zinc on the expression of metallothionein isoforms in hippocampus of stressed rats].

OBJECTIVE: This study was conducted to evaluate the effects of different doses of zinc on the expression of metallothionein isoforms in hippocampus of stressed rats. METHODS: The animal model of psychological stress was developed by restraint stress for four weeks. Wistar rats were randomly assigned to eight groups as follows: control group, zinc deficiency group, pair-feed group, zinc complementarity group and their corresponding stressed groups. RESULTS: In zinc deficiency group, plasm zinc content was decreased, while in zinc complementarity group it's slightly increased. On the one hand, the expressions of metallothionein in brain and MT-1 mRNA, MT-3 mRNA in hippocampus were downregulated in zinc deficiency group, however, their expressions were evidently enhanced in stressed zinc deficiency group. On the other hand, inductions of metallothionein and it' s mRNAs in zinc complementarity group were increased, furthermore, stressed zinc complementarity group has more significantly yield of metallothionein and it' s mRNAs. In addition, the levels of plasma cortisol, IL-6, IL-1 and NO were increased clearly in zinc deficiency group and stressed zinc deficiency group. CONCLUSION: Our results suggested that zinc deficiency may decrease while zinc complementarity increase the expressions of metallothionein in brain and MT-1 mRNA, MT-3 mRNA in hippocampus, moreover, stress can increased their expressions dramatically. The impairment of stress on body may be involved with the nutrition status of zinc, and zinc deficiency can lower the body's resistibility to stress.

The Arabidopsis thaliana TCP transcription factors: A broadening horizon beyond development.

The TCP family of transcription factors is named after the first 4 characterized members, namely TEOSINTE BRANCHED1 (TB1) from maize (Zea mays), CYCLOIDEA (CYC) from snapdragon (Antirrhinum majus), as well as PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR1 (PCF1) and PCF2 from rice (Oryza sativa). Phylogenic analysis of this plant-specific protein family unveils a conserved bHLH-containing DNA-binding motif known as the TCP domain. In accordance with the structure of this shared domain, TCP proteins are grouped into class I (TCP-P) and class II (TCP-C), which are suggested to antagonistically modulate plant growth and development via competitively binding similar cis-regulatory modules called site II elements. Over the last decades, TCPs across the plant kingdom have been demonstrated to control a plethora of plant processes. Notably, TCPs also regulate plant development and defense responses via stimulating the biosynthetic pathways of bioactive metabolites, such as brassinosteroid (BR), jasmonic acid (JA) and flavonoids. Besides, mutagenesis analysis coupled with biochemical experiments identifies several crucial amino acids located within the TCP domain, which confer the redox sensitivity of class I TCPs and determine the distinct DNA-binding properties of TCPs. In this review, developmental functions of TCPs in various biological pathways are briefly described with an emphasis on their involvement in the synthesis of bioactive substances. Furthermore, novel biochemical aspects of TCPs with respect to redox regulation and DNA-binding preferences are elaborated. In addition, the unexpected participation of TCPs in effector-triggered immunity (ETI) and defense against insects indicates that the widely recognized developmental regulators are capable of fine-tuning defense signaling and thereby enable plants to evade deleterious developmental phenotypes. Altogether, these recent impressive breakthroughs remarkably advance our understanding as to how TCPs integrate internal developmental cues with external environmental stimuli to orchestrate plant development.

[Effect of zinc on the corticosterone-induced injury of primary cultured rat hippocampal neurons].

The effect of zinc on the damage of primary cultured hippocampal neurons induced by corticosterone (CORT) was studied. Neuronal injury and expression of NMDA receptor subunits (NR1,NR2A,NR2B) mRNA were detected by using in situ staining and RT-PCR, respectively. Neurons treated with 5 micromol/L CORT for 24 h showed decreased survival rates and increased apoptotic rates compared with the controls; co-application of CORT and 10 or 100 micromol/L Zn(2+) attenuated apoptotic rates while 250 micromol/L Zn(2+) worsened CORT-induced neuronal injury. Expression of NR1, NR2B mRNA in neurons treated by 5 micromol/L CORT for 24 h was significantly increased, while those concurrently added with 10 or 100 micromol/L Zn(2+) showed no changes. No statistic difference in NR2A mRNA was obtained under any treatment. These results suggest that zinc can bilaterally regulate neuronal injuries induced by CORT, among while NMDA receptors probably play an important role.

[Effects of zinc deficiency on bone mineralization and its mechanism in rats].

OBJECTIVE: To study the influence of zinc deficiency on bone mineralization. METHODS: Thirty Wistar rats were randomly divided into three groups with ten in each group, i.e., zinc-deficient group (ZD), control group, and pair-fed group. Histomorphological changes of bone mineralization, bone mineral content and bone density, bone contents of zinc, calcium, phosphorus, magnesium, manganese, copper and hydroxyproline, and serum levels of parathyroid hormone, calcitonin and osteocalcin in the rats were measured. RESULTS: The results showed that the mineral deposit rate and bone contents of zinc, phosphorus and hydroxyproline, and serum levels of calcitonin and osteocalcin lowered significantly in ZD group, as compared with those in the control and pair-fed groups, with (3.26 +/- 0.34) micro m/d, (64.54 +/- 2.34) g/kg, (54.4 +/- 9.5) mg/kg, (9.28 +/- 1.62) g/kg, (41.2 +/- 13.5) micro g/L, (82 +/- 30) micro g/L in ZD group; (5.37 +/- 0.53) micro m/d, (69.01 +/- 4.05) g/kg, (117.4 +/- 8.0) mg/kg, (11.31 +/- 1.30) g/kg, (68.3 +/- 14.4) micro g/L, (131 +/- 46) micro g/L in the control group; and (5.45 +/- 0.30) micro m/d, (67.81 +/- 3.56) g/kg, (106.7 +/- 8.4) mg/kg, (10.88 +/- 1.47) g/kg, (63.7 +/- 12.0) micro g/L, (120 +/- 52) micro g/L in the pair-fed group, respectively. While the time for mineralization lag and osteoid maturation obviously prolonged, (1.08 +/- 0.19) d and (7.12 +/- 2.30) d in ZD group, (0.39 +/- 0.06) d and (2.21 +/- 1.12) d in the control group, and (0.40 +/- 0.06) d and (2.12 +/- 0.58) d in the pair-fed group, respectively. In addition, bone mineral content and bone density and serum parathyroid hormone in ZD group decreased significantly and were lower than those in the control group, but not significantly different from those in the pair-fed group. There were no significant difference in femoral contents of calcium, magnesium, manganese and copper between the ZD group and the control and pair-fed groups. CONCLUSIONS: Zinc deficiency could lower the contents of parathyroid hormone and calcitonin in blood circulation affecting bone mineral deposit and causing defect in bone mineralization.

[Effect of zinc deficiency on the behavior and calcium status of hippocampal neurons in rats].

In order to explore the effects of zinc deficiency on the behavior, [Ca2+]i and active CaM contents of hippocampal cells of rats, 21 male Wistar rats were randomly divided into 3 groups, i.e. zinc deficiency group (ZD), pair-fed group (PF), and control group (CT) fed with zinc deficiency (ZD group) and normal diets (PF and CT group). At the end of the third week, the behavior in open-field test was observed. Then all the rats were killed and [Ca2+]i concentration and active CaM contents of hippocampal cells were determined by Fura-2 two wave-length fluorophotometry and flow cytometry respectively. It showed a significant difference between ZD and CT group in behavior was observed. [Ca2+]i concentration of ZD group was remarkably higher than that of CT and PF group. Active CaM contents of ZD and PF groups were significantly lower than that of CT group, and the active CaM content of ZD was also significantly lower than that of PF group. It showed that the effect of zinc deficiency on behaviors may be related with the changes in calcium status of hippocampal cells in growing rats.

[Zinc deficiency on pathological changes of femur epiphyseal growth plate in rats].

To study zinc deficiency on pathological changes of femur epiphyseal growth plate in rats thirty Wistar rats were randomly divided into three groups: zinc-deficient group (Zd), control group (Ctr), and pair-fed group (Zp) to study the effects of zinc deficiency on femur epiphyseal growth plate of rats and the mechanism involved. After 8 weeks feeding, the histomorphology of right femur indicated that chondrocytes in the epiphyseal growth plate of Zd group were generally ill-organized and mis-shaped. The number of chondrocytes decreased. Trabecular bone in the epiphyseal of Zd group were also ill-organized, scarce and slim. The cavities of marrow in Zd animals were significantly larger than those of Ctr and Zp. The volume of trabecular bone, the mean trabecular plate density of Zd rats were significantly decreased, but their mean trabecular plate space was significantly increased. In addition, the Zd animals had significantly lower concentration of osteocalcin and growth hormone in sera. The above results suggested that zinc deficiency impaired proliferation and differentiation of chondrocytes and balance between osteoblast and osteoclast function by reduce growth hormone levels in sera. The lack of zinc in diet resulted in disorder of bone molding and ultrastructure.

[Supplementation with micronutrients attenuating stress injuries in rats].

OBJECTIVE: To observe the protective effects of compound micronutrients (CMN) on stress-induced injury of the rats. METHODS: The experimental rats were fed with diet added micronutrients in small, medium and large dose respectively. The stress animal model was established by feet-electric shock. The behaviors in open-field test, hormons, metallothionein (MT) and the antioxidant ability of the rats were detected. RESULTS: Compared with control group, the abnormal behaviors in open-field test, increased cortisol level in serum, decreased epinephrine and norepinephrine contents in brain were observed in stress rats. Also stress induced significantly changes of MT levels in liver and brain, and declined antioxidant ability in serum and enhanced lipid peroxidation in liver of the animals. The most indicators mentioned above were obviously improved by supplementation with CMN for 6 weeks. CONCLUSION: Supplementation with CMN was beneficial to improve the stress adapting ability and to attenuate the stress-induced injuries in rats.