食药用菌酸乳制作中深层发酵滤液添加量的比较

利用深层发酵培养基对两种食药用菌（香菇、猴头菌）进行深层发酵培养,然后分别将香菇（猴头菌）发酵滤液、奶粉、无菌水按不同比例配制成相应的复原奶,并接种乳酸菌制成酸乳。同时检测不同比例发酵滤液添加量所制得的酸乳的营养和理化特性,选择出了最佳比例的滤液添加量,即香菇滤液添加量以3份较好,而猴头菌则以4份滤液添加量最佳。     

Effect of red mold rice supplements on serum and meat cholesterol levels of broilers chicken

Monacolin K is a secondary metabolite produced by Monascus species. It was found that it is able to decrease cholesterol levels. In this study, red mold rice (RMR) was added to the diet of Arbor Acres broiler chickens, and the cholesterol level in meat, as well as the concentration of triglyceride, the high-density lipoprotein cholesterol (HDL-C), and the low-density lipoprotein cholesterol (LDL-C) in the serum were evaluated. Four-week-old broilers are studied and divided into four groups in that each group contains 15 subjects. A 3-week experimental feeding trial was conducted in which three groups of broilers were fed 2.0, 5.0, and 8.0% of RMR (RMR groups) within their diet, respectively, and the result was compared to the control group. The results indicated that for each RMR group, the cholesterol content was significantly lower than that of the control group; in addition, their meat products contain higher level of unsaturated fatty acids. Triglyceride and cholesterol concentration in serum was also found to be considerably lower in RMR groups when compared to control group. Finally, in RMR groups, HDL-C/LDL-C and HDL-C/cholesterol ratios were all higher than those of the control group. In short, the results demonstrated that the cholesterol levels could be lowered by adding RMR to the diet of chickens.     

Kinetics of the sodium-dependent glutamine transporter in human intestinal cell confluent monolayers.

The intestinal epithelium metabolism of glutamine plays a critical role in inter-organ nitrogen flow. Although it is known that glutamine is the primary oxidative energy source and nucleotide precursor in intestinal cells, the luminal uptake of glutamine by the apical surface of enterocytes is poorly understood. In this study we have uncovered the sodium-dependent transporter system responsible for L-glutamine uptake by the apical membrane of a human intestinal epithelial cell line. The sodium-dependent Michaelis constant (Km) = 247 +/- 45 microM glutamine, and Jmax = 4.44 +/- 0.65 x 10(-9) mole min-1(mg protein)-1 (37 degrees C). Glutamine shares the transporter with alanine, as demonstrated by unlabeled glutamine inhibition of [3H]alanine uptake kinetics with a purely competitive-type inhibition pattern, and glutamine inhibition Ki = 205 +/- 18 microM by Dixon analysis. The inhibition pattern for a series of amino acid analogs indicated that this intestinal apical membrane sodium-dependent transporter for glutamine is distinct from any other transport system found in membranes of non-intestinal cells.     

Nitric oxide inhibits nociceptive transmission by differentially regulating glutamate and glycine release to spinal dorsal horn neurons

Nitric oxide (NO) is involved in many physiological functions, but its role in pain signaling remains uncertain. Surprisingly, little is known about how endogenous NO affects excitatory and inhibitory synaptic transmission at the spinal level. Here we determined how NO affects excitatory and inhibitory synaptic inputs to dorsal horn neurons using whole-cell recordings in rat spinal cord slices. The NO precursor L-arginine or the NO donor SNAP significantly increased the frequency of glycinergic spontaneous and miniature inhibitory postsynaptic currents (IPSCs) of lamina II neurons. However, neither L-arginine nor SNAP had any effect on GABAergic IPSCs. L-arginine and SNAP significantly reduced the amplitude of monosynaptic excitatory postsynaptic currents (EPSCs) evoked from the dorsal root with an increase in paired-pulse ratio. Inhibition of the soluble guanylyl cyclase abolished the effect of L-arginine on glycinergic IPSCs but not on evoked monosynaptic EPSCs. Also, inhibition of protein kinase G blocked the increase in glycinergic sIPSCs by the cGMP analog 8-bromo-cGMP. The inhibitory effects of L-arginine on evoked EPSCs and high voltage-activated Ca(2+) channels expressed in HEK293 cells and dorsal root ganglion neurons were abolished by blocking the S-nitrosylation reaction with N-ethylmaleimide. Intrathecal injection of L-arginine and SNAP significantly increased mechanical nociceptive thresholds. Our findings suggest that spinal endogenous NO enhances inhibitory glycinergic input to dorsal horn neurons through sGC-cGMP-protein kinase G. Furthermore, NO reduces glutamate release from primary afferent terminals through S-nitrosylation of voltage-activated Ca(2+) channels. Both of these actions probably contribute to inhibition of nociceptive transmission by NO at the spinal level.     

Cloning of the flap endonuclease-1 gene in Bombyx mori and identification of an antiapoptotic function

The flap endonuclease-1 (FEN-1) gene is involved in DNA replication and repair, and it maintains genomic stability as well as the accuracy of DNA replication under normal growth conditions. However, FEN-1 also plays an important role in apoptosis and cancer development. We cloned the BmFEN-1 gene from Bombyx mori, which was 1343?bp in length and possessed an 1143?bp ORF (123-1266). It consists of seven introns and eight exons that encode a protein with 380 amino acids that has the typical XPG domain. The N-terminal motif is located at amino acids 95-105, and the proliferating cell nuclear antigen interaction motif is located at amino acids 337-344. RNA interference-mediated reduction of BmFEN-1 expression induced cell cycle arrest in S phase in BmE-SWU1?cells. These results suggest that BmFEN-1 can inhibit apoptosis and promote cell proliferation.     

Upgrading of high-boiling fraction of bio-oil in supercritical methanol

In this work, the upgrading reactions of high-boiling fraction (HBF) of bio-oil were carried out over a series of supported mono- and bi-metallic catalysts under the supercritical methanol condition. During these reactions, esterification and cracking (alcoholysis and hydrocracking) were the two dominant processes. PtNi/MgO exhibited good performance, and gave a high yield (72.4 wt.%) of refined oil. The acid-base properties of the supports have an important effect on the coke deposition on the catalyst surface. The acidic catalysts gave the somewhat lower product yields, but tended to inhibit coking reaction. This would improve the life of the catalysts in the practical applications. The refined oil is believed to be a potential substitute or partial substitute for the fossil transportation fuel.     

Single amino acid changes in the virus capsid permit coxsackievirus B3 to bind decay-accelerating factor

Many coxsackievirus B isolates bind to human decay-accelerating factor (DAF) as well as to the coxsackievirus and adenovirus receptor (CAR). The first-described DAF-binding isolate, coxsackievirus B3 (CB3)-RD, was obtained during passage of the prototype strain CB3-Nancy on RD cells, which express DAF but very little CAR. CB3-RD binds to human DAF, whereas CB3-Nancy does not. To determine the molecular basis for the specific interaction of CB3-RD with DAF, we produced cDNA clones encoding both CB3-RD and CB3-Nancy and mutated each of the sites at which the RD and Nancy sequences diverged. We found that a single amino acid change, the replacement of a glutamate within VP3 (VP3-234E) with a glutamine residue (Q), conferred upon CB3-Nancy the capacity to bind DAF and to infect RD cells. Readaptation of molecularly cloned CB3-Nancy to RD cells selected for a new virus with the same VP3-234Q residue. In experiments with CB3-H3, another virus isolate that does not bind measurably to DAF, adaptation to RD cells resulted in a DAF-binding isolate with a single amino acid change within VP2 (VP2-138 N to D). Both VP3-234Q and VP2-138D were required for binding of CB3-RD to DAF. In the structure of the CB3-RD-DAF complex determined by cryo-electron microscopy, both VP3-234Q and VP2-138D are located at the contact site between the virus and DAF.     

Metabolic engineering of isoflavone genistein in Brassica napus with soybean isoflavone synthase

Genistein, 4′,5,7-trihydroxyisoflavone, is an isoflavonoid compound predominantly restricted to legumes and known to possess phyto-oestrogenic and antioxidative activities. The key enzyme that redirects phenylpropanoid pathway intermediates from flavonoids to isoflavonoids is the isoflavone synthase (IFS). Brassica napus is a non-legume oilseed crop with vegetative tissues producing phenylpropanoids and flavonoids, but does not naturally accumulate isoflavones due to the absence of IFS. To demonstrate whether exogenous IFS is able to use endogenous substrate to produce isoflavone genistein in oilseed crop, the soybean IFS gene (GmIFS2) was incorporated into B. napus plants. The presence of GmIFS2 in B. napus was shown to direct the synthesis and accumulation of genistein derivatives in leaves up to 0.72 mg g⁻¹ DW. In addition, expression levels for most B. napus genes in the phenylpropanoid pathway were altered. These results suggest that the heterologous GmIFS2 enzyme is functionally active at using the B. napus naringenin as a substrate to produce genistein in oilseed rape.     

Taccasubosides A-D, four new steroidal glycosides from Tacca subflabellata

By analyzing the steroidal content of fresh whole plants of Tacca subflabellata (Taccaceae), we isolated one sapogenin and eight glycosides with four kinds of steroidal skeletons including four new glycosides, named taccasubosides A-D (1-4), together with five known compounds. Among them, compound 1 is the first pentacyclic sterol glycoside with 6-6-6-5-6 fused rings. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic hydrolysis. The cytotoxicity of the selected steroidal glycosides (1-4, 8, and 9) was evaluated in vitro against five human cancer cell lines. Compound 9 showed significant inhibitory activity against all five cell lines.