A protective role of resveratrol against the effects of immobilization stress in corpora lutea of mice in early pregnancy

In the present study, we aimed to investigate a protective role for resveratrol against the effects of immobilization stress on corpora lutea(CL) of mice in early pregnancy. A total of 45 early-pregnant mice were divided into no immobilization stress(NIS) group, immobilization stress(IS) group, and immobilization and resveratrol treatment(IS+RES) group(n=15). Mice were immobilized in plastic tubes(50 mL) for 3 h per day during day 1 to 7 of pregnancy. In the IS+RES group, 5 mg kg–1 d–1 of resveratrol was administered just prior to application of stress. We analyzed apoptotic activity in CL by Western blotting analysis(WB), transmission electron microscopy(TEM), and immunohistochemistry(IHC). Serum progesterone levels were examined with radioimmunoassay(RIA). IHC results showed that the intensity of positive staining for Bax was increased, and for Bcl-2 was decreased in CL after IS, while resveratrol treatment reversed the positive staining for Bax and Bcl-2. WB revealed that immobilization stress up-regulated the expression of Bax and caspase-9, and downregulated Bcl-2 expression, while resveratrol treatment attenuated the effects of immobilization stress on the expression of Bax, Bcl-2 and caspase-9. According to our TEM results, apoptosis as defined by chromatin condensation was found in CL after immobilization stress, while resveratrol inhibited the apoptosis. We also demonstrated that immobilization stress decreased progesterone concentrations and ovarian expression of StAR, while resveratrol restored the concentrations of progesterone and expression of StAR back to normal. These results indicated that immobilization stress induced luteal regression while resveratrol inhibited luteal regression, suggesting that resveratrol plays a protective role on corpora lutea of mice during early pregnancy.     

Sugarcane Bagasse Biochar: Preparation,Characterization, and Its Effects on Soil Properties and Zinc Sorption-desorption

ABSTRACT

Application of alkaline biochar has been proposed as an alternative to lime for remediation of acidic soils. However, questions remain as to how the reactions and fate of metals in acidic soils can be affected by biochar amendment. To find out how biochar addition might affect sorption-desorption behavior of zinc (Zn) in acidic soils, a soil with an initial pH value of 4.67 was treated with different levels [0 (control), 1%, 3%, and 6%] of biochar produced from pyrolysis of sugarcane bagasse at 600°C and incubated for 30 days under 80% of water holding capacity. At the end of the incubation period, important soil chemical properties were measured and batch isotherm experiments were performed to determine soil Zn sorption-desorption parameters. The results showed that the biochar-amended soils had higher pH values (up to 2.5 pH units), electrical conductivity (up to 2.66 times), and cation exchange capacities (up to 42%) relative to the un-amended acidic soil. Biochar addition also led to significant enhancements in soil exchangeable calcium, magnesium, sodium, and potassium cations. Both sorption and desorption isotherm experiments revealed the significantly higher capacity of the biochar-amended soils to retain Zn than that of the control. Moreover, the biochar-amended soils exhibited a higher affinity for Zn sorption than did the un-amended acidic one. It can be concluded that biochar derived from sugarcane bagasse could serve as a good amendment material to reclaim acidic soils and to reduce Zn mobility and toxicity in acidic metal-contaminated soils.     

Affinity Purification of Angiotensin Converting Enzyme Inhibitory Peptides from Wakame (Undaria Pinnatifida) Using Immobilized ACE on Magnetic Metal Organic Frameworks

Angiotensin-I-converting enzyme (ACE) inhibitory peptides derived from marine organism have shown a blood pressure lowering effect with no side effects. A new affinity medium of Fe₃O₄@ZIF-90 immobilized ACE (Fe₃O₄@ZIF-90-ACE) was prepared and used in the purification of ACE inhibitory peptides from Wakame (Undaria pinnatifida) protein hydrolysate (<5 kDa). The Fe₃O₄@ZIF-90 nanoparticles were prepared by a one-pot synthesis and crude ACE extract from pig lung was immobilized onto it, which exhibited excellent stability and reusability. A novel ACE inhibitory peptide, KNFL (inhibitory concentration 50, IC₅₀ = 225.87 μM) was identified by affinity purification using Fe₃O₄@ZIF-90-ACE combined with reverse phase-high performance liquid chromatography (RP-HPLC) and MALDI-TOF mass spectrometry. Lineweaver–Burk analysis confirmed the non-competitive inhibition pattern of KNFL, and molecular docking showed that it bound at a non-active site of ACE via hydrogen bonds. This demonstrates that affinity purification using Fe₃O₄@ZIF-90-ACE is a highly efficient method for separating ACE inhibitory peptides from complex protein mixtures and the purified peptide KNFL could be developed as a functional food ingredients against hypertension.     

制动应激对孕猪海马结构神经元可塑性的影响

旨在研究限位栏饲养造成的制动应激对妊娠母猪神经元可塑性的影响，本研究选取6头8~9月龄配种成功的巴马小型母猪，随机分成两组，应激组（n=3）限位栏饲养，对照组（n=3）自由环境饲养，其余饲养管理一致。于妊娠第18天处死孕猪，取其海马和血液，使用ELISA、放射免疫法检测相关激素水平，制作海马石蜡切片进行尼氏染色和镀银染色后观察神经元丢失率、树突复杂度以及树突棘数量等，并采用Western blot检测海马脑源性神经营养因子（BDNF）表达水平。结果显示，应激组血浆中促肾上腺皮质激素释放激素（CRH）、促肾上腺皮质激素（ACTH）、皮质醇（COR）水平均显著上升（P≤0.05），齿状回（DG）和CA3区出现神经元丢失现象，CA3区锥形细胞树突复杂度下降，神经元成熟树突棘和未成熟树突棘数量均显著降低，DG的成熟树突棘数量显著降低，且海马内的BDNF蛋白表达量较对照组降低70.6%（P≤0.01）。因此，制动应激减弱了孕猪大脑海马中CA3区和DG的神经元可塑性。     

Correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress

AIM:To explore the correlation between fecal metabolites and body weight/food intake in rats after chronic immobilization stress (CIS). METHODS:Healthy male Sprague-Dawley (SD) rats (n=48) were randomly divided into control group and CIS group. The rats in CIS group were subjected to 3 h of immobilization stress a day for 21 consecutive days, and the rats in control group were kept for 21 d without stress intervention. The behaviors in open-field test (OFT) and elevated plus-maze test (EPM test), the sucrose consumption, the serum D-xylose content, and the small bowel transit rate were detected. The fecal metabolites were determined by ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR) technique, and differential metabolites in the rats of 2 groups were analyzed by multivariate statistics. The correlation between body weight/food intake and above indexes of CIS rats were observed by Pearson correlation analysis. RESULTS:Compared with the control rats, the body weight of CIS rats was increased slowly and the food intake was decreased significantly (P<0.01). In the OFT, both the total and central distance covered in CIS rats were reduced significantly than those in control group within 5 min (P<0.01). In the EPM test, the residence time in open-arms of CIS rats within 5 min was shortened dramatically than those in the control group (P<0.01). The content of serum D-xylose and the sucrose consumption of the rats after stress for 21 d were decreased markedly (P<0.05). The small bowel transit rate of CIS rats was lower than that of control rats, but no statistical difference was observed (P>0.05). Acetate, butyrate, glucose, propionate, glutamate, ribose, pimelate, lactate, alanine, valerate, total 10 kinds of differential metabolites in fecal samples were detected, and the 10 kinds of metabolites in CIS rats were higher than that of the control rats (P<0.05). Pearson correlation analysis showed that food intake of CIS rats was negatively correlated with metabolites of acetate and pimelate (P<0.05), and no correlation between body weight and above indexes was found. CONCLUSION:Under the CIS condition, there are certain correlations between food intake and metabolites of acetate and pimelate, but the mechanism still need further study.     

Effects of root zone trenching on soil nitrogen dynamics in Japanese cedar and cypress plantations

The effects of root exclusion and planted tree species on soil nitrogen (N) dynamics were examined at two plantations, one planted with Japanese cedar and the other with Japanese cypress. We set up ten 1 × 1 × 0.2-m-deep trenched sites and ten untrenched control sites at each plantation. We measured the pool size and leaching of inorganic N at each site for 2 years and the net N mineralization 1 and 2 years after trenching. Despite similar soil conditions, the cedar plantation showed higher net N mineralization than the cypress plantation. Stopped tree uptake of N was expected to cause an increased pool size and leaching of inorganic N at the trenched sites. Nevertheless, we found no significant increase in those variables at both plantations. The trenched cypress sites showed no decrease in the net N mineralization during the 2 years after trenching. However, the net nitrification at the trenched cypress sites increased remarkably at the deeper horizons in comparison with that at the control sites. Enhanced nitrification might result from improved ammonium availability through root exclusion. Net N mineralization at the trenched cedar sites decreased more than 60% compared with that at the control sites 2 years after trenching. Higher nitrification potential at the cedar plantation and enhanced nitrification potential at the trenched cypress sites never resulted in increased leaching of N, due to added fine root litter which acted as an immobilization agent for excess N, thus preventing N loss.     

Retention of available P in acid soils of tropical and subtropical evergreen broad-leaved forests

Precipitation of mineral phosphate is often recognized as a factor of limiting the availability of P in acidic soils of tropical and subtropical forests. For this paper, we studied the extractable P pools and their transformation rates in soils of a tropical evergreen forest at Xishuangbanna and a subtropical montane wet forest at the Ailao Mountains in order to understand the biogeochemical processes regulating P availability in acidic soils. The two forests differ in forest humus layer; it is deep in the Ailao forest while little is present in the Xishuangbanna forest. The extractable P pools by resin and sodium-bicarbonate decreased when soil organic carbon content was reduced. The lowest levels of extractable P pools occurred in the surface (0–10 cm) mineral soils of the Xishuangbanna forest. However, microbial P in the mineral soil of the Xishuangbanna forest was twice that in the Ailao forest. Potential rates of microbial P immobilization were greater than those of organic P mineralization in mineral soils for both forests. We suggest that microbial P immobilization plays an essential role in avoiding mineral P precipitation and retaining available P of plant in tropical acidic soils, whereas both floor mass accumulation and microbial P immobilization function benefit retaining plant available P in subtropical montane wet forests. Translated from Acta Ecologica Sinica, 2006, 26(7): 2,294–2,300 [译自: 生态学报]     

壳聚糖固化绿色木霉A10产纤维素酶的研究

用壳聚糖作为载体、戊二醛作为交联剂来固定化木霉A10产纤维素酶。试验发现交联剂的最佳交联浓度为5%。通过L9（34）正交试验,结果显示用该方案来固定化木霉A10号产纤维素酶是可行的,并且固定化效率最高为69.12%,最佳条件为固定化pH值为8、物料比为1∶0.03、处理时间为12 h。固定化后,酶对热的稳定性明显提高;固定化酶的最适pH比原酶要低,往酸性方向移,且在弱酸性范围内受pH的影响较小;表观米氏常数减小。半衰期为35 d左右。     

模板法制备多孔交联脂肪酶聚集体碳酸钙及其特性

针对传统交联脂肪酶聚集体(cross-linked lipase aggregates,CLEAs)表面密实、比表面积小、无太多孔隙结构、在催化过程中存在扩散限制、影响酶催化效率等问题,该文通过脂肪酶、氯化钙、碳酸钠、硫酸铵共沉淀制备脂肪酶/碳酸钙微球,再加入二硫苏糖醇(dithiothreitol,DTT)进行脂肪酶交联自组装,然后用乙二胺四乙酸二钠(EDTA)去除碳酸钙模板剂,制得多孔交联脂肪酶聚集体微球(p-CLEAs),对其制备条件、结构特征、酶学性质进行研究。结果表明,最佳制备条件为:Ca^2+浓度0.35 mol/L、脂肪酶与Ca^2+比例5:1、沉淀剂饱和度80%、沉淀pH值为8、沉淀时间45 min、DTT体积分数0.2%、交联时间40 min。与常规CLEAs相比,所制备的p-CLEAs在甲醇耐受性、热稳定性和pH值稳定性方面均有明显改善,4℃保藏6个月,仍保持较高的活性。其结构稳定,形貌、孔道尺寸可调控,呈多孔结构,这种多孔结构使得底物分子更容易进入脂肪酶的活性位点,不仅降低了传质限制,还提高了催化效率,具有较高的催化活性。     

Litterfall,decomposition, and nitrogen release in two age groups of trees in Casuarina equisetifolia plantations in the dry tropical Vindhyan plateau,India

Litterfall, decomposition, and N release in 5-year-old and 8-year-old plantations of Casuarina equisetifolia (Forst.) in the dry tropical region of the Vindhyan plateau were studied during 1989–1990. Maximum litterfall occurred in May. The total litterfall ranged from 7.2 to 9.9t ha^-1 year^-1 in the 5-year-old stand and from 11.3 to 12.7t ha^-1 year^-1 in the 8-year-old stand over the 2-year period. Photosynthetic branchlets contributed 87–95% to the total litter. The relative decomposition rates of litter components of the ash-free mass were highest in the rainy months (4.7 to 9.9mg g^-1 day^-1) followed by winter (2.8 to 3.6 mg g^-1 day^-1) and lowest in the summer months (1.7 to 3.0 mg g^-1 day^-1). Similar patterns were observed for N release. The annual decay constant was highest for cone litter and lowest for photosynthetic branchlets. During decomposition, the photosynthetic branchlets showed N immobilization in November and April, the twig litter in March, and the roots in January and February. N release per unit area (g m^-2) was maximum from the photosynthetic branchlets (5.3–6.3) followed by cones (4.4) > roots (3.4) > twigs (2.6–3.2). The combination of the litter C:N ratio, moisture, and temperature with the relative decomposition rate in a multiple regression analysis explained 66–84% of the variability in mass loss and 58–66% of the variability in N release.