Vapor Pressure Measurement and Correlation of 2-Methyl-Butanol Acetate Containing Calcium Chloride

The CaCl2 solubility in 2-methyl-butanol acetate and the vapor pressure of 2-methyl-butanol acetate containing CaCl2 were measured in the range of 90-135°C and from very low salt concentration to saturation.The experimental data were correlated with two equations,a modified Antoine equation with the dissolved salt taken into account and a nonrandom two liquid-electrolyte（e-NRTL）model.Both models are in good agreement with the experimental data.This study provides essential physical data for further investigation of vapor-liquid equilibrium system containing salt.

Comparative Study of Effect of Addition of Calcium Carbonate and Clay on the Performance Properties of Polyvinyl Acetate Wood Glue

Polyvinyl alcohol (PVA) stabilized Polyvinyl acetate (PVAc) dispersions-based wood adhesive has poor water and heat resistance. Recently, the addition of fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive. Inorganic fillers have unique characteristics to improve the performance of adhesive, such as small size, high surface energy and surface hardness. Hence, the present work investigates the applicability of calcium carbonate and clay incorporated 3% in situ emulsion polymerization PVAc wood adhesive. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with 3% calcium carbonate and 3% clay were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was reduced in the case of the addition of calcium carbonate and increased in the case of clay. The mechanical properties like tensile strength of adhesives with calcium carbonate and clay were measured by a universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that clay can improve bonding strength as compared to calcium carbonate of PVAc adhesive in wet conditions. The hardness of PVAc films was also changed positively by the addition of calcium carbonate and clay. Thermal stability of PVAc was significantly improved as calcium carbonate and clay were added to PVAc. Here, we did a comparative study of the effect of the addition of calcium carbonate and clay filler materials in situ polymerization of PVAc on their different properties.

Effects of Calcium Element on Biomass and Effective Constituents Contents in Blumea balsamifera in Slow Growth Period of Winter

The one-year-old seedlings of Blumea balsamifera （L.） DC. were applied with CaCl2.H2O that supplied Ca in slow growth period of winter three times. The heights, ground diameters, leaf lengths, leaf widths and biomasses of B. balsamifera plants were measured. In addition, the relative contents of total flavones in different parts of B. balsamifera were determined by UV spectrophotometry, and the absolute contents of total flavones were calculated. The relative contents of L-borneol in leaves of B. balsamifera were determined by GC, and the absolute contents of L- borneol were calculated. The results showed that calcium element significantly in- creased the biomasses in leaves, stems and roots of B. balsamifera in slow growth period of winter. The leaf biomass of B. balsamifera in the 5 g/L CaCl2-H2O treat- ment group was significantly higher than those in the other three treatment groups. The leaf biomasses of B. balsamifera in the 10 and 15 g/L CaCl2.H2O treatment groups were significantly higher than that in the CK, with 3.03 and 2.65 times, re- spectively. The application of Ca inhibited the accumulation of total flavones relative contents, but significantly increased the total flavones absolute contents in different parts of B. balsamifera. The relative and absolute contents of L-borneol in the 5 g/L CaCl2 .H2O treatment group were 0.22% and 0.22 g, which were increased by 37.50%, 22.22%, 37.50% and 100%, 100%, 450%, respectively compared with those in the 0, 10 and 15 g/L CaCl2.H2O treatment groups. The Ca element could signifi- cantly promote the accumulation of biomasses in leaves, stems and roots, as well as the absolute contents of total flavones and L-borneol in B. balsamifera in slow growth period of winter.

Altered expression of stromal interaction molecule(STIM)-calcium release-activated calcium channel protein(ORAI) and inositol1,4,5-trisphosphate receptors(IP_3Rs)in cancer:will they become a new battlefield for oncotherapy?

The stromal interaction molecule(STIM)-calcium release-activated calcium channel protein(ORAI) and inositol1,4,5-trisphosphate receptors(IP_3Rs) play pivotal roles in the modulation of Ca^(2+)-regulated pathways from gene transcription to cell apoptosis by driving calcium-dependent signaling processes.Increasing evidence has implicated the dysregulation of STIM-ORAI and IP_3Rs in tumorigenesis and tumor progression.By controlling the activities,structure,and/or expression levels of these Ca^(2+)-transporting proteins,malignant cancer cells can hijack them to drive essential biological functions for tumor development.However,the molecular mechanisms underlying the participation of STIM-ORAI and IP_3Rs in the biological behavior of cancer remain elusive.In this review,we summarize recent advances regarding STIM-ORAI and IP_3Rs and discuss how they promote cell proliferation,apoptosis evasion,and cell migration through temporal and spatial rearrangements in certain types of malignant cells.An understanding of the essential roles of STIM-ORAI and IP_3Rs may provide new pharmacologic targets that achieve a better therapeutic effect by inhibiting their actions in key intracellular signaling pathways.

CHEMICAL MODIFICATION OF THE SURFACE OF CALCIUM ALGINATE GEL BEADS

The chemical modification of the surface of calcium alginate gel beads (CAGB) via grafting copolymerization with vinyl acetate (VAc) was studied. The optimum reaction conditions with activation and graft copolymerization two steps were explored. First, 5 grams CAGB with 2.5 mm initial diameter was initiated with 0.0493 mol/L K2S2O8 at 51 °C for 30 min in 15 mL 1 % PVA/H2O. Then 4.34 moi/L VAc was added dropwise and the reaction was allowed to proce at 48 °C for 3 h. The grafting efficiency could come up to 30%. It was found the stability of modified CAGB in the air and in electrolyte solutions was greatly improved.

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca^(2+)-ATPase in cardiomyocytes of Adriamycin-treated rats

Objective: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin 1 (cTnl) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca2+]) and activity of sarcoplosnic Ca2+-ATPase (SRCa2+-ATPase) in Adriamycin (ADR)-treated rats. Methods: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnl. CK-MB was detected by monoclonal antibody, Myo[Ca2+] was detected by fluorescent spectrophotometry and the activity of SRCa2+-ATPase was detected by inorganic phosphate method. Results: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnl and CK-MB, while at the same time decreased calcium concentration and increased SRCa2+-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). Conclusions: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa2+-ATPase activity in cardiomyocytes.

Liraglutide directly protects cardiomyocytes against reperfusion injury possibly via modulation of intracellular calcium homeostasis

Background Liraglutide is glucagon-like peptide-1 receptor agonist for treating patients with type 2 diabetes mellitus. Our previous studies have demonstrated that liraglutide protects cardiac function through improving endothelial function in patients with acute myocardial infarction undergoing percutaneous coronary intervention. The present study will investigate whether liraglntide can perform direct protective effects on cardiomyocytes against reperfusion injury. Methods In vitro experiments were performed using H9C2 cells and neonatal rat ventricular cadiomyocytes undergoing simulative hypoxia/reoxygenation （H/R） induction. Cardiomyocytes apoptosis was detected by fluorescence TUNEL. Mitochondrial membrane potential （AWm） and intracellular reactive oxygen species （ROS） was assessed by JC-1 and DHE, respectively. Fura-2/AM was used to measure intracellular Ca2＋ concentration and calcium transient. Immtmofluorescence staining was used to assess the expression level of sarcoplasmic reticulum Ca2＋-ATPase （SERCA2a）. In vivo experiments, myocardial apoptosis and expression of SERCA2a were detected by colorimetric TUNEL and by immunofluorescence staining, respectively. Results In vitro liraglutide inhibited cardiomyotes apoptosis against H/R. △mψ of cardiomyocytes was higher in liraglntide group than H/R group. H/R increased ROS production in H9C2 cells which was attenuated by liraglutide. Liraglutide significantly lowered Ca2＋ overload and improved calcium transient compared with H/R group, lmmunofluorescence staining results showed liraglutide promoted SERCA2a expression which was decreased in H/R group. In ischemia/reperfusion rat hearts, apoptosis was significantly attenuated and SERCA2a expression was increased by liraglutide compared with H/R group. Conclusions Liraglutide can directly protect cardiomyocytes against reperfusion injury which is possibly through modulation of intracellular calcium homeostasis.

Polydatin attenuated food allergy via store-operated calcium channels in mast cell

AIM: To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and antiallergic activity. METHODS: After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwent PD treatment for 4 d, all the rats were stimulated by 100 mg/mL OVA for24 h and then sacrificed for the following experiments. The small intestines from all the groups were prepared for morphology examination by hematoxylin and eosin staining. We also used a smooth muscle organ bath to evaluate the motility of the small intestines. The OVA-specific immunoglobulin E (IgE) production and interleu-kin-4 (IL-4) levels in serum or supernatant of intestinal mucosa homogenates were analyzed by enzyme-linked immunosorbent assay (ELISA). Using toluidine blue stain, the activation and degranulation of isolated rat peritoneal mast cells (RPMCs) were analyzed. Release of histamine from RPMCs was measured by ELISA, and regulation of PD on intracellular Ca 2+ mobilization was investigated by probing intracellular Ca 2+ with fluo-4 fluo-rescent dye, with the signal recorded and analyzed. RESULTS: We found that intragastric treatment with PD significantly reduced loss of mucosal barrier integrity in the small intestine. However, OVA-sensitization caused significant hyperactivity in the small intestine of allergic rats, which was attenuated by PD administration by 42% (1.26 ± 0.13 g vs OVA 2.18 ± 0.21 g, P < 0.01). PD therapy also inhibited IgE production (3.95 ± 0.53 ng/mL vs OVA 4.53 ± 0.52 ng/mL, P < 0.05) by suppressing the secretion of Th2-type cytokine, IL-4, by 34% (38.58 ± 4.41 pg/mLvs OVA 58.15 ± 6.24 pg/mL, P < 0.01). The ratio of degranulated mast cells, as indicated by vehicles (at least five) around the cells, dramatically increased in the OVA group by 5.5 fold (63.50% ± 15.51% vs phosphate-buffered saline 11.15% ± 8.26%, P < 0.001) and fell by 65% after PD treatment (21.95% ± 4.37% vs OVA 63.50% ± 15.51%, P < 0.001). PD mediated attenuation of mast cell degranulation was further confirmed by decreased histamine levels in both serum (5.98 ± 0.17 vs OVA 6.67 ± 0.12, P < 0.05) and intestinal mucosa homogenates (5.83 ± 0.91 vs OVA 7.35 ± 0.97, P < 0.05). Furthermore, we demonstrated that administration with PD significantly decreased mast cell degranulation due to reduced Ca 2+ influx through store-operated calcium channels (SOCs) (2.35 ± 0.39vs OVA 3.51 ± 0.38,P < 0.01).CONCLUSION: Taken together, our data indicate that PD stabilizes mast cells by suppressing intracellular Ca 2+ mobilization, mainly through inhibiting Ca 2+ entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.

Methodological study on endogenous calcium absorptivity using rats and 41Ca tracing

Elemental calcium plays an important role in human physiology. In order to study the relationship between Ca-intake, Ca-chemical formulation, and Ca-absorptivity, a balance experiment using a ^(41)Ca tracer technique in SD rats was conducted to measure the endogenous fecal calcium and true absorption of calcium. Apparent absorption of calcium was measured as a control to the endogenous calcium labeling experiment. These results show that by using ^(41)Ca labeled endogenous calcium in vivo, researchers could obtain the true calcium absorption data without extrinsic labeling. Therefore, the method was not affected by the chemical structure or type of calcium supplement and might be used in evaluating the absorptivity of marketed calcium supplements.

Effect of Calcium Aluminate Cement Variety on the Hydration of Portland Cement in Blended System

Two kinds of CACs with different monocalcium aluminate（CA） contents were used in the PC/CAC（PAC） mixtures. Effects of CA and CACs on the properties of PAC were analyzed by setting times and the compressive strength tests, and also by means of calorimetry, XRD, DTA-TG and ESEM. The experimental results show that the compressive strength of the PAC mortars decreases with increasing content of CAC while it declines sharply with a higher content of CA in CAC. Compared with neat PC paste, the content of calcium hydroxide in hydrates of PAC paste decreases significantly, and the hydration time of PC is prominently prolonged. Additionally, the higher the content of CA in CAC, the more obviously the hydration of PC is delayed, confi rming that the CA phase in CAC plays an important role in the delay of PC hydration.

Simultaneous CO_(2) capture and thermochemical heat storage by modified carbide slag in coupled calcium looping and CaO/Ca(OH)2 cycles

The simultaneous CO_(2) capture and heat storage performances of the modified carbide slag with byproduct of biodiesel were investigated in the process coupled calcium looping and CaO/Ca(OH)2 thermochemical heat storage using air as the heat transfer fluid.The modified carbide slag with by-product of biodiesel exhibits superior CO_(2) capture and heat storage capacities in the coupled calcium looping and heat storage cycles.The hydration conversion and heat storage density of the modified carbide slag after 30 heat storage cycles are 0.65 mol·mol^(-1) and 1.14 GJ·t^(-1),respectively,which are 1.6 times as high as those of calcined carbide slag.The negative effect of CO_(2) in air as the heat storage fluid on the heat storage capacity of the modified carbide slag is overcome by introducing CO_(2) capture cycles.In addition,the CO_(2) capture reactivity of the modified carbide slag after the multiple calcium looping cycles is enhanced by the introduction of heat storage cycles.By introducing 10 heat storage cycles after the 10th and 15th CO_(2) capture cycles,the CO_(2) capture capacities of the modified carbide slag are subsequently improved by 32%and 43%,respectively.The porous and loose structure of modified carbide slag reduces the diffusion resistances of CO_(2) and steam in the material in the coupled process.The formed CaCO_(3)in the modified carbide slag as a result of air as the heat transfer fluid in heat storage cycles decomposes to regenerate CaO in calcium looping cycles,which improves heat storage capacity.Therefore,the modified carbide slag with by-product of biodiesel seems promising in the coupled calcium looping and CaO/Ca(OH)_(2) heat storage cycles.

Effect of Low Dose Radiation on Intracellular Calcium and Protein Kinase C in Lymphocytes

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming micc With 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+], mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBl with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed

Mechanisms of retinal neuroprotection of calcium dobesilate：therapeutic implications

Current treatments for diabetic retinopathy （DR） are based on laser photocoagulation and intravitreal injections of corti- costeroids or anti-vascular endothelial growth factor （VEGF） agents. These treatments are applicable only at advanced stages of the disease. In addition, they are expensive, require a vitreo- retinal specialist and are associated with significant adverse ef- fects. Therefore, new pharmacological treatments for the early stages of the disease are needed.

Effects of Trinitrotoluene on Serum Phosphorylase A Activities and on Calcium Contents in Men and Rats

Wistar rats were exposed to trinitrotoluene (TNT) for 6 weeks. After initiation of TNT exposure, serum phosphorylase A activities and calcium contents were assayed for every 2 weeks. Both of these 2 parameters increased in rats treated with 50 and 100 mg TNT/kg b.w. at 3 intervals. Serum phosphorylase A activities and calcium contents of TNT exposure worker increased too.

Role of calcium and magnesium infusion in prevention of oxaliplatin neurotoxicity. A phase III trial

Objective： This study is a prospective randomized, double-blind, placebo-controlled study to evaluate the effect of calcium and magnesium （Ca/Mg） infusion on amelioration of oxaliplatin neuropathy, the dose-limiting toxicity. Methods： Sixty patients with resected colorectal carcinoma （CRC） planned to receive adjuvant oxaliplatin-containing regimen were randomly assigned to two arms; Arm A： patients received Ca/Mg were given as 1 gm Ca gluconate and 1 gm MgSO4 in 250 mL of intravenous （IV） solution over 30 rain pre and post oxaliplatin infusion, and Arm B： patients received 250 mL of IV solution without Ca/Mg over 30 min pre and post oxaliplatin infusion. Primary outcome was to assess percentage of patients with oxaliplatin-induced neurotoxicity. Neurotoxicity was assessed according to the National Cancer Institute Common Terminology Criteria forAdverse Events （NCI-CTCAE） version 3.0. Results： Sixty patients in both arms were assessed, 30 with Ca/Mg infusion and 30 without. Patients developed neurotoxicity in arm A were significantly lower than that in arm B after the end of treatment; 7 （23.3%） and 14 （46.6%） respectively （P 〈 0.05）, and significantly lower duration of neuropathy in months （8 ± 2.5 vs 18 ±3） respectively （P 〈 0.001）. Conclusion： Use of IV Ca/Mg showed a statistically significant reduction of peripheral neuropathy （PN） in patients with CRC receiving oxaliplatin in the adjuvant settings.

EFFECT OF ELECTROACUPUNCTURE AND CALCIUM-CHANNEL INHIBITORS ON CYTOPLASMIC FREE CALCIUM CONCENTRATION OF MOUSE BRAIN CELLS

Objective: To study the effect of electroacupuncture (EA) and Verapamil and Nifedipine (calcium channel inhibitors) on free calcium concentrations of cells and intrasynaptosomes in hypothalamus (HT), periaqueductual grey matter (PAG) and hippocampus (HIP) of mice. Methods: The female ICR mice were randomly divided into control, EA, CaCl2 and CaCl2+EA groups (n=8 in each group). Pain threshold was detected by using radiation-heat irradiation-induced tail flick method. EA (8 Hz, a suitable stimulating strength, dense-sparse waves and duration of 30 min) was applied to“Shuigou” (水沟 GV 26) and “Chengjiang” (承浆CV 24). CaCl2 (10 μL, 0.2 μmol/L) was injected into the lateral cerebral ventricle of mice after EA. The concentrations of cytosolic free calcium ([Ca 2+]i) in HIP, PAG, HT cell suspension specimen and hippocampal intrasynaptosome suspension of mice were determined by the fluorescent calcium indicator Fura-2-AM and a spectrofluorometer. Results: During EA analgesia, the intracellular free [Ca 2+]i in HT and PAG specimens and intrsynaptosomal [Ca 2+]i of the 3 cerebral regions decreased considerably (P<0.05～0.01), but that in hippocampal cell suspension increased significantly (P<0.01) in comparison with control group. The concentrations of hippocampal intrasynaptosomal free [Ca 2+]i decreased significantly after adding Verapamil and Nifedipine to the extracted hippocampal intrasynaptosomal specimen. Microinjection of CaCl2 into lateral ventricle had no apparent influence on degree of analgesia (DA)% and intracellular and intrasynapsotomal [Ca 2+]i, but significantly lower DA% and reduce changes of cytosolic and intrasynaptosomal [Ca 2+]i induced by EA stimulation. Conclusion: Calcium ion in the neurons and intrasynaptosome of HT, PAG and HIP is involved in electroacupuncture analgesia.

Plasma membrane calcium pump regulation by metabolic stress

The plasma membrane Ca2+-ATPase(PMCA)is an ATPdriven pump that is critical for the maintenance of low resting[Ca2+]i in all eukaryotic cells.Metabolic stress, either due to inhibition of mitochondrial or glycolytic metabolism,has the capacity to cause ATP depletion and thus inhibit PMCA activity.This has potentially fatal consequences,particularly for non-excitable cells in which the PMCA is the major Ca2+efflux pathway.This is because inhibition of the PMCA inevitably leads to cytosolic Ca2+ overload and the consequent cell death.However,the relationship between metabolic stress,ATP depletion and inhibition of the PMCA is not as simple as one would have originally predicted.There is increasing evidence that metabolic stress can lead to the inhibition of PMCA activity independent of ATP or prior to substantial ATP depletion.In particular,there is evidence that the PMCA has its own glycolytic ATP supply that can fuel the PMCA in the face of impaired mitochondrial function.Moreover, membrane phospholipids,mitochondrial membrane potential,caspase/calpain cleavage and oxidative stress have all been implicated in metabolic stress-induced inhibition of the PMCA.The major focus of this review is to challenge the conventional view of ATP-dependent regulation of the PMCA and bring together some of the alternative or additional mechanisms by which metabolic stress impairs PMCA activity resulting in cytosolic Ca2+ overload and cytotoxicity.

苹果sMdCAX11基因的功能分析与鉴定

【目的】深入分析苹果sMdCAX11(去掉NRR区域的MdCAX11)基因功能。【方法】分别利用蜜脆苹果果实和拟南芥材料,采用过表达sMdCAX11的试验方法,观察果实、叶片等各组织的表型,并测定不同组织的矿质元素含量,同时对苹果MdCAX11基因启动子区域进行预测分析以及启动子转录活性分析。【结果】瞬时过表达sMdCAX11的苹果果肉颜色变褐,并出现皱缩;同时过表达sMdCAX11的苹果果肉和拟南芥叶片的总Ca含量明显下降,且元素比值(K+Mg)/Ca明显升高。【结论】sMdCAX11基因过表达可导致植株组织的元素分配不均,不同元素间的比例失衡。

A Study on the Mechanism Regulating Acetate to Propionate Ratio in Rumen Fermentation by Dietary Carbohydrate Type

The research direction of our team is nutrition and physiology of ruminants, including dietary nutrition metabolism and rumen microorganisms. Previous research has shown that ruminal acetate-to-propionate ratio is related to diet utilization efficiency. At present, it is believed that the main factors affecting the ruminal acetate-to-propionate ratio are the degradation rate of the diet and the rumen microbial structure, but the main mechanism is unclear. This study found that the effect of ruminal acetate-to-propionate ratio was not affected by the concentration of the fermentation substrate, but was affected by the structure of the rumen microbiota. We believe that changes in the rumen microflora structure are the main mechanism for regulating the ruminal acetate-to-propionate ratio. This will help people to further understand the rumen physiology, thereby gradually improving feed conversion efficiency and reducing production costs. Abstract: In order to explore the mechanism by which diet regulates the acetate-to-propionate molar ratio (A: P ratio), we compared the effect on rumen fermentation parameters and the microbiome by altering the ratio of dietary concentrates to roughage ratio and calcium pyruvate infusion. The test animals were Laoshan dairy goats, and were fed continuously through an automatic feeder. The test groups were fed a base diet of low concentrates, and intraruminally infused with calcium pyruvate at two concentrations. The infusion concentrations were derived from the difference in the rate of carbohydrate degradation of the high and low concentrate diets, and they were artificially set such that the high concentration infusion group was infused with twice the concentration as the low concentration infusion group. The control groups were fed high concentrate (6:4) and low concentrate (3:7) diets, respectively. The following results were obtained by measuring rumen fermentation parameters and microbial composition: the rumen A: P ratio was significantly lower in the high-concentrate diet group than in the low concentrate diet group (P < 0.05). Infusion of low concentration calcium pyruvate had no significant effect on rumen A: P ratio (P > 0.05), while infusion of high concentration calcium pyruvate significantly increased the rumen A: P ratio (P < 0.05). Relative to goats fed the low concentrate diet, those fed the high concentrate diet had a greater abundance of microbes related to propionate production and a reduced abundance of microbes related to fiber degradation. Infusion of pyruvate had no significant effect on rumen microbial structure. The above results indicate that increasing the concentration of the fermentation substrate without affecting the composition of the microflora does not reduce the A: P ratio. Microbiological results showed that the A: P ratio was more closely related to the rumen microflora structure. Therefore, it is believed that rumen microflora structure is the main mechanism regulating A: P ratio in rumen fermentation.

Effects of Arecoline on Calcium Channel Currents and Caffeine-induced Calcium Release in Isolated Single Ventricular

The effects of Arecoline (Are) on calcium m obilization were investigated. In isolated single ventricular m yocyte of guinea pig,patch clamp whole cell recording techniques were used to record the current of L - type calcium channel and cytosolic Ca2 + level ([Ca2 + ]i) labeled with fluo- rescence probe Fluo- 3/ AM was m easured under a laser scanning confocal microscope.Results re- vealed that Are(3- 10 0 μm ol/ L) could inhibit L- type calcium current in a concentration- depen- dent manner and the value of IC50 was33.73μm ol/ L (n=5 ) .In the absence of extracellular calci- um,the resting levels of[Ca2 + ]i was not affected by Are(n=6 ,P>0 .0 5 ) ,but pretreatment with Are(30 μmol/ L) could significantly inhibit the[Ca2 + ]i elevation induced by caffeine(10 m mol/ L,n=6 ,P<0 .0 1) .It was concluded that Are could inhibit not only calcium influx through L- type calcium channel but also calcium release from sarcoplasm ic reticulum.