氯化钙中硫酸根含量的测定方法

生产氯化钙的原材料进卤液是生产纯碱的废液,此液中含有硫酸根离子,导致成品氯化钙中含有硫酸根离子,有些用户要求硫酸根离子含量。本人通过大量试验证明重量分析法对氯化钙中硫酸根离子的测定,结果比较准确,实验条件好掌握。     

The effects of eggshell calcium (Biomin H®) and its combinations with alfacalcidol (1α-hydroxyvitamin D3) and menaquinone-7 (vitamin K2) on ovariectomy-induced bone loss in a rat model of osteoporosis

The purpose of this study was to investigate the impact of eggshell calcium (Biomin H^® dietary supplement) and its combinations with alfacalcidol (1α-hydroxyvitamin D₃) and menaquinone-7 (vitamin K₂) on ovariectomy-induced bone loss in rats. Adult female rats (n = 48) were divided into 6 groups of 8 individuals each: sham-operated rats (SHAM); ovariectomized (OVX) rats untreated; OVX rats treated with Biomin H^® (BIO); OVX rats simultaneously receiving Biomin H^®, vitamin D₃ (BIO + D₃); OVX rats simultaneously treated with Biomin H^®, vitamin K₂ (BIO + K₂) and OVX rats treated with Biomin H^®, vitamin D₃, vitamin K₂ (BIO + D₃ + K₂) during 8 weeks. Biochemical parameters, bone mineral density (BMD), bone mineral content (BMC) and femoral bone microstructure were determined. Plasma calcium and phosphate were increased in BIO + D₃ and BIO + D₃ + K₂ groups as compared to OVX. Alkaline phosphatase was elevated in OVX, BIO versus SHAM, BIO + D₃ + K2 groups. When compared to OVX group, decreased urine deoxypyridinoline was observed in all treated groups and femoral BMD, BMC were higher in BIO, BIO + D₃, BIO + D₃ + K₂ groups. The BIO + K₂ rats had similar densitometrical values than OVX individuals. Microcomputed tomography revealed increased trabecular relative bone volume (due to an increase in trabecular number) in BIO + D₃, BIO + D₃ + K₂ as compared to OVX. The higher relative bone volume in BIO + D₃, BIO + D₃ + K₂ groups was also accompanied by an increase in bone surface. In the cortical bone, an enhanced periosteal bone apposition was identified in BIO, BIO + D₃, BIO + K₂, BIO + D₃ + K₂ groups. The rats from BIO + D₃ + K₂ group had a higher area of primary osteon's vascular canals. In BIO + D₃, BIO + K₂, BIO + D₃ + K₂ groups, an increased area of secondary osteons was determined in comparison with OVX. Our results indicate the beneficial effect of triple application of Biomin H^®, vitamin D₃, vitamin K₂, as well as simultaneous administration of Biomin H^®, vitamin D₃ on the inhibition of ovariectomy-induced bone loss in a rat model of osteoporosis.     

氯化钙处理对采后蓝莓果实品质的影响

为研究不同浓度氯化钙处理对采后蓝莓品质的影响,本试验分别采用15、30 g/L的氯化钙及去离子水(对照)浸泡处理采后蓝莓10 min,并于4℃下贮藏。以14 d为1个测定周期,对采后蓝莓果实的基本生理指标、原果胶和可溶性果胶含量、抗性相关酶活性、超氧阴离子自由基清除能力和总抗氧化能力进行测定。结果表明:与对照组相比,氯化钙处理可延缓采后蓝莓果实腐烂率、失重率的上升,抑制硬度、可溶性固形物含量、原果胶含量的下降,降低呼吸强度以及多酚氧化酶(PPO)、过氧化物酶(POD)活性,诱导过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)活性,提升超氧阴离子自由基清除能力及总抗氧化能力。氯化钙处理对采后蓝莓果实有较好的保鲜效果,且以15 g/L氯化钙处理效果最佳。     

Effects of Zn2+ on Ca2+ uptake by mitochondria and endoplasmic reticulum in permeabilized tilapia gill cells

An intracellular ATP-dependent Ca²⁺ pumping mechanism, distinct from mitochondrial Ca²⁺ accumulation, was identified within tilapia gill cells. Cell suspensions treated with 0.003% saponin, which selectively permeabilizes the plasma membrane, were used to characterize the Ca²⁺ sequentering mechanisms as endoplasmic reticulum and mitochondria and to determine the effect of Zn²⁺ on their Ca²⁺ storing activity. Of the Ca²⁺ taken up by the endoplasmic reticulum, 80% was released by IP₃ (10 mol l^–1). The Ca²⁺ pump of the endoplasmic reticulum was 2.5 times less sensitive to Zn²⁺ (IC₅₀=0.05 nmol l^–1) than was the mitochondrial uptake mechanism (IC₅₀=0.20 nmol l^–1). The results indicate that Ca²⁺ is stored predominantly within the endoplasmic reticulum at 0.1 mol l^–1 and that this storing capacity is seriously attenuated by namomolar concentrations Zn²⁺.     

不同砧木砂糖橘树体内Ca素含量的分布特点

【目的】探讨不同砧木砂糖橘树体内Ca素含量的分布特点。【方法】采用整株肢解法,于果实成熟期(2008-01-05)将7年生酸砧和枳砧砂糖橘树体分为23个部位,分别测定各个部位的生物量和Ca素含量。【结果】枳砧砂糖橘根部的Ca素含量显著高于酸砧,枝干、叶和果实Ca素含量与酸砧差异不显著。砂糖橘枝干和枝干木质部Ca素含量均随着部位粗度的增加而降低,而枝干皮部Ca素含量变化则相反,枝干和枝干木质部Ca素含量变动幅度以枳砧较大,枝干皮部则以酸砧较大;砂糖橘果皮Ca素含量显著高于果肉;叶片和叶柄之间Ca素含量差异不显著。在2种砧木中,除根颈外,砂糖橘根部Ca素含量均为须根侧根主根,但枳砧根颈、须根Ca素含量均显著高于酸砧。【结论】砧木对砂糖橘根部Ca素含量有显著影响,对叶、枝干、果实Ca素含量影响甚微。     

Mechanisms involved in the cytosolic calcium ion elevation induced by activating factors in chicken and rat phagocytes

The aim of the present study was to determine the mechanism of cytosolic calcium ion concentration [Ca²⁺]_i elevation in chicken and rat phagocytes stimulated with phorbol myristate acetate (PMA), leukotriene B₄ (LTB₄), formyl‐methionyl‐leucyl‐phenylananine (fMLP) and Saccaromyces cerevisiae culture supernatant (SCS). Pretreatment with EGTA completely suppressed the PMA‐induced [Ca²⁺]_i elevation in rat and chicken phagocytes, suggesting that all the [Ca²⁺]_i elevation induced in the PMA‐stimulated rat and chicken phagocytes was attributable to the influx of extracellular Ca²⁺. On the other hand, the elevation of LTB₄‐, FMLP‐ and SCS‐induced [Ca²⁺]_i was only partially suppressed by ethyleneglycol‐bis (β‐aminoethyl)‐N,N,N′,N′‐tetraacetic acid ethylene (EGTA) pretreatment of phagocytes. The results indicated that two pathways of [Ca²⁺]_i elevation, recruitment from the intracellular Ca²⁺ store and influx of extracellular Ca²⁺, are involved in the [Ca²⁺]_i elevation of LTB₄‐, fMLP‐ and SCS‐stimulated phagocytes. In fMLP‐stimulated rat neutrophils, [Ca²⁺]_i elevation showed a two‐phase pattern in which the time lag between the first and second phase was approximately 1 min. The EGTA treatment of the fMLP‐stimulated cells induced a reduction of the first phase level and a disappearance of the second phase. The reason for the special influence of EGTA observed in fMLP‐stimulated cells is unknown, but the disappearance of the second phase of the [Ca²⁺]_i may be elicited by the EGTA‐induced decrease of the first phase [Ca²⁺]_i elevation that depends on IP₃ and diacylglycerol induced by fMLP.     

Effect of autophagy on L-type calcium channel current induced by gp120V3 in hippocampus neurons

AIM: To observe the influence of autophagy on L-type calcium channel current induced by gp120V3 loop in hippocampal neurons.METHODS: Hippocampal neurons were exteriorized from the newborn rats within 1 d and primarily cultured for 7 d. The neurons were divided into 2 parallel groups, namely control group, gp120V3 group, autophagy inhibitor 3-MA group, gp120V3 + 3-MA group; control group, gp120V3 group, autophagy activator rapamycin group, gp120V3 + rapamycin group. Whole-cell pathch-clamp was used to record L-type calcium channel current. RESULTS: Compared with control group, the density of L-type calcium channel current increased in gp120V3 group and 3-MA group(P<0.05). Compared with gp120V3 group, the density of L-type calcium channel current increased in gp120V3 + 3-MA group(P<0.05). Compared with control group, the density of L-type calcium channel current decreased in rapamycin group(P<0.05). Compared with gp120V3 group, the density of L-type calcium channel current increased in gp120V3 + rapamycin group(P<0.05).CONCLUSION: Autophagy may be involved in the gp120V3 loop-mediated L-type calcium channels in hippocampus neurons.     

Calcium‐Dependent Tolerant Response of Cell Wall in Maize Mesocotyl Under Flooding Stress

The aim of the present study was to find out the effect of calcium on flooded maize seedlings by anatomical and ultra‐structural analyses and by measuring the enzyme activity and gene expression of polygalacturonase (PG) and superoxide dismutase (SOD). For this, maize seeds were placed to germinate in germination paper saturated with CaCl₂ 0.75 %. Then, 4‐day‐old seedlings were subjected to flooding in the presence or absence of CaCl₂. Mesocotyl sections were sampled daily for the anatomical and ultra‐structural analyses, RT‐qPCR and activity of SOD and PG. The results showed that the presence of calcium in the flooding buffer increases the tolerance of maize seedlings by 1 day when compared to seedlings flooded in the absence of this element. The reason for this longer survival is that calcium maintains the integrity of the cell wall and attenuates the effects of oxidative stress. Owing to this fact, the seedlings remained alive and firm for up to 7 days.