Authors:C. Wen-Sheng, L. Yi, Z. Chuan-Pei, L. Qiang-Guo, and Q. Song-Sheng
The solid-state coordination reactions of lanthanum chloride with alanine and glycine, and lanthanum nitrate with alanine
have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in
2 mol L-1 HCl solvent of these three solid-solid coordination reactions have been measured using an isoperibol calorimeter. From the
results and other auxiliary quantities, the standard molar formation enthalpies have been determined to be ΔfHmθ[La(Ala)3Cl33H2O(s), 298.2 K]= -3716.3 kJ mol-1, ΔfHmθ [La(Gly)3Cl35H2O(s), 298.2 K]= -4223.0 kJ mol-1 and ΔfHmθ [La(Ala)4(NO3)3H2O(s), 298.2 K]= -3867.57 kJ mol-1, respectively.
Authors:L. Ruan, Y. Liu, Z. Gao, P. Shen, and Q. Sheng
The thermogenic curves of the aerobic metabolism of the three strains of Bacillus thuringiensisB.t. A, B.t. B and B.t. C have been determined by using an LKB-2277 BioActivity Monitor. B.t. A was the host bacterium without foreign gene. B.t. B and B.t. C were constructed by transforming different foreign genes into the host B.t. A, respectively. B.t. B expressed erythromycin resistant gene, while B.t. C expressed both erythromycin resistant gene and tyrosinase gene. The heat flow rate of these strains is B.t. A> B.t. B >B.t. C. These results indicated that there is obvious interrelation between expression of foreign genes and heat flow rate of
Authors:Q. Du, L. Zhang, H. Cui, K. Wang, L. Xiu, and L. Sheng
Cleavage of glucosinolates with myrosinase yields thioglycosidic compounds which have cancer chemoprevention activity. In this paper, glucosinolates in an extract (2.0 g) of broccoli seeds (Brassica oleracea var. italica) were separated by high-speed countercurrent chromatography (HSCCC) with the solvent system n-butanol-acetonitrile-10% ammonium sulfate solution 1:0.5:2.2 (v/v) to yield five glucosinolate compounds after desalting and decolorizing by MCI column chromatography. The five compounds, 7-methylsulfinylheptyl glucosinolate (22.4 mg), 4-pentenyl glucosinolate (33.6 mg), 3-butenyl glucosinolate (24.0 mg), 4-methylsulfinylbutyl glucosinolate (161.4 mg), and 3-methylsulfinylpropyl glucosinolate (29.6 mg), were identified by ESI-MS, 1H NMR and 13C NMR. The purity of the products was >98%, and 7-methylsulfinylheptyl glucosinolate was obtained from broccoli seeds for the first time.
Authors:L. Qiang-Guo, H. Yi, L. Xu, Y. Li-Juan, X. Sheng-Xiong, Y. De-Jun, and L. Yi
The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C7H5O3)2·(C9H6NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard
molar enthalpies of solution of [NdCl3·6H2O(s)], [2C7H6O3(s)], [C9H7NO(s)] and [Nd(C7H5O3)2·(C9H6NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at
298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction
was determined to be ΔrHmΘ=117.89±0.37 kJ mol−1. From data in the literature, through Hess’ law, the standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H7NO)(s) was estimated to be ΔfHmΘ[Nd(C7H5O3)2·(C9H6NO)(s), 298.15 K]=−2031.80±8.6 kJ mol−1.
Authors:A. Abderrahmane, L. Yi, G. Wen-Ying, S. Ping, and Q. Song-Sheng
In this paper, a promoter-probe plasmid pKK232-8 was used as a vector, which functioned in Escherichia coli TG1 host. The plasmid DNA fragments from Pseudomonas maltophilia AT18 chromosome DNA active as promoter inEscherichia coli TG1, the promoter function was studied by means of microcalorimetry, the promoter is about 800 bp DNA, it can promote the chloramphenicol
(Cm) gene in plasmid pKK232-8, the Cm resistance level is about 80 μg mL–1, the promoter activity is high. It implicates that there are probably many promoters in Pseudomonas maltophilia AT18 chromosome. All these information is readily obtained by an LKB 2277-204 heat conduction microcalorimeter. Microcalorimetry
is a quantitative, inexpensive, and versatile method for microbiological genetic research.
Authors:Z. Fengqi, G. Hongxu, L. Yang, H. Rongzu, C. Pei, G. Sheng-li, Y. Xu-wu, and S. Qizhen
The constant-volume combustion energies of
the lead salts of 2-hydroxy-3,5-dinitropyridine (2HDNPPb) and 4-hydroxy-3,5-dinitropyridine
(2HDNPPb(s) and 4HDNPP(s)),
were determined as –4441.922.43 and –4515.741.92
kJ mol–1 , respectively, at 298.15 K. Their
standard enthalpies of combustion, Δcm
H θ(2HDNPPb(s) and 4HDNPPb(s), 298.15 K), and standard enthalpies of formation,
Δrm H θ(2HDNPPb(s) and 4HDNPPb(s),
298.15 K) were as –4425.812.43, –4499.631.92 kJ
mol–1 and –870.432.76, –796.652.32
kJ mol–1 , respectively. As two combustion
catalysts, 2HDNPPb and 4HDNPPb can enhance the burning rate and reduce the
pressure exponent of RDX–CMDB propellant.
Authors:X.R. Zhi, Z.Y. Zhang, R.Y. Li, L. Chang, P.P. Jia, N. Sheng, and L.T. Zhang
A new, sensitive, and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS/MS) has been developed for the quantification of six flavonoids (sophoricoside, genistin, genistein, rutin, quercetin, and kaempferol) in rat bile and urine. The sample pretreatment was simple by liquid-liquid extraction. Sulfamethalazole was used as internal standard (IS). During method development, the effect of extraction volume, mobile phase composition, column temperature, and injection volume were varied to optimize sensitivity and achieve a run time as short as possible. Chromatographic separation was accomplished on a C18 column with a simple linear gradient elution within 9 min. Full validation of the assay was in accordance with the requirement of the validation of the method in vivo and implemented including specificity, linearity, accuracy, precision, recovery, and matrix effect. This is the first report on determination of the major flavones in rat bile and urine after oral administration of Fructus Sophorae extract. The method has been used successfully in excretion studies of six major flavonoids in rat bile and urine.
Authors:H.Q. Zhao, L. Wang, J. Hong, X.Y. Zhao, X.H. Yu, L. Sheng, C.Z. Hang, Y. Zhao, A.A. Lin, W.H. Si, and F.S. Hong
Salt stress impaired Mn imbalance and resulted in accumulation of ROS, and caused oxidative stress to plants. However, very little is known about the oxidative damage of maize roots caused by exposure to a combination of both salt stress and Mn deprivation. Thus the main aim of this study was to determine the effects of a combination of salt stress and Mn deprivation on antioxidative defense system in maize roots. Maize plants were cultivated in Hoagland’s media. They were subjected to 80 mM NaCl administered in the Mn-present Hoagland’s or Mn-deficient Hoagland’s media for 14 days. The findings indicated that the growth and root activity of maize seedlings cultivated in a combination of both salt stress and Mn deprivation were significantly inhibited; the compatible solute accumulation, malondialdehyde, carbonyl, 8-OHdG, and ROS were higher than those of the individual salt stress or Mn deprivation as expected. Nevertheless, the antioxidative enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase, glutathione-S-transferase and antioxidants such as ascorbic acid, glutathione and thiol were lower than those of the individual salt stress or Mn deprivation. In view of the fact that salt stress impaired Mn nutrition of maize seedlings, the findings suggested that Mn deprivation at the cellular level may be a contributory factor to salt-induced oxidative stress and related oxidative damage of maize roots.