奥得福尔制剂的药效学研究与临床

对奥得福尔制剂的药效学定量杀菌试验、抗病毒试验及临床应用的结果表明： 得福尔制剂原液,１：１稀释液及１：５稀释液对大肠杆菌、金黄色葡萄球菌和白色念珠菌作用１０ｍｉｎ,杀灭率均可达９９．９％以上;消毒液放置室温下稳定,有机物的存在对杀灭作用有轻度影响,但杀灭率仍可达９９．９％以上;体外抗病毒试验结果表明,该制剂的主要抗病毒功效成分－黄精多糖,对单纯疱疹病毒的空斑抑制率达到１００％;稳定性试验表明,该     

SOS3 function in plant salt tolerance requires N-myristoylation and calcium binding

The salt tolerance gene SOS3 (for salt overly sensitive3) of Arabidopsis is predicted to encode a calcium binding protein with an N-myristoylation signature sequence. Here, we examine the myristoylation and calcium binding properties of SOS3 and their functional significance in plant tolerance to salt. Treatment of young Arabidopsis seedlings with the myristoylation inhibitor 2-hydroxymyristic acid caused the swelling of root tips, mimicking the phenotype of the salt-hypersensitive mutant sos3-1. In vitro translation assays with reticulocyte showed that the SOS3 protein was myristoylated. Targeted mutagenesis of the N-terminal glycine-2 to alanine prevented the myristoylation of SOS3. The functional significance of SOS3 myristoylation was examined by expressing the wild-type myristoylated SOS3 and the mutated nonmyristoylated SOS3 in the sos3-1 mutant. Expression of the myristoylated but not the nonmyristoylated SOS3 complemented the salt-hypersensitive phenotype of sos3-1 plants. No significant difference in membrane association was observed between the myristoylated and nonmyristoylated SOS3. Gel mobility shift and (45)Ca(2)+ overlay assays demonstrated that SOS3 is a unique calcium binding protein and that the sos3-1 mutation substantially reduced the capacity of SOS3 to bind calcium. The resulting mutant SOS3 protein was not able to interact with the SOS2 protein kinase and was less capable of activating it. Together, these results strongly suggest that both N-myristoylation and calcium binding are required for SOS3 function in plant salt tolerance.     

Diverse functions of antioxidants

All biological organisms have developed a defense system against oxidative stress, which is comprised of many kinds of antioxidants. Antioxidants are classified by function into four categories; preventive antioxidants; radical scavenging antioxidants; repair and de novo antioxidants; and adaptation. Radical scavenging antioxidants have the greatest advantage. Although the activities of radical scavenging antioxidant are determined by several factors, their chemical structure is of key importance. Furthermore, radical scavenging antioxidants have been explored to have a novel function by which they regulate gene expression of cell.     

Concurrent enteric helminth infection modulates inflammation and gastric immune responses and reduces helicobacter-induced gastric atrophy

Helicobacter pylori is causally associated with gastritis and gastric cancer. Some developing countries with a high prevalence of infection have high gastric cancer rates, whereas in others, these rates are low. The progression of helicobacter-induced gastritis and gastric atrophy mediated by type 1 T-helper cells may be modulated by concurrent parasitic infection. Here, in mice with concurrent helminth infection, helicobacter-associated gastric atrophy was reduced considerably despite chronic inflammation and high helicobacter colonization. This correlated with a substantial reduction in mRNA for cytokines and chemokines associated with a gastric inflammatory response of type 1 T-helper cells. Thus, concurrent enteric helminth infection can attenuate gastric atrophy, a premalignant lesion.     

Orthostatic hypotension in aging humans

We tested the hypothesis that hypotension occurred in older adults at the onset of orthostatic challenge as a result of vagal dysfunction. Responses of heart rate (HR) and mean arterial pressure (MAP) were compared between 10 healthy older and younger adults during onset and sustained lower body negative pressure (LBNP). A younger group was also assessed after blockade of the parasympathetic nervous system with the use of atropine or glycopyrrolate and after blockade of the beta(1)-adrenoceptor by use of metoprolol. Baseline HR (older vs. younger: 59 +/- 4 vs. 54 +/- 1 beats/min) and MAP (83 +/- 2 vs. 89 +/- 3 mmHg) were not significantly different between the groups. During -40 Torr, significant tachycardia occurred at the first HR response in the younger subjects without hypotension, whereas significant hypotension [change in MAP (DeltaMAP) -7 +/- 2 mmHg] was observed in the elderly without tachycardia. After the parasympathetic blockade, tachycardiac responses of younger subjects were diminished and associated with a significant hypotension at the onset of LBNP. However, MAP was not affected after the cardiac sympathetic blockade. We concluded that the elderly experienced orthostatic hypotension at the onset of orthostatic challenge because of a diminished HR response. However, an augmented vasoconstriction helped with the maintenance of their blood pressure during sustained LBNP.     

Control of foodborne pathogens during sufu fermentation and aging

Control of the foodborne pathogens Escherichia coli O157:H7, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes during sufu fermentation was evaluated. Before fermentation, pathogens were inoculated onto tofu (substrate for sufu) at 5 log cfu/g or 3 log cfu/g, and starter culture (Actinomucor elegans) was inoculated at 3 log cfu/g. After 2 days of fermentation at 30 degrees C, the four pathogens reached 7 to 9 log cfu/g, and the mold count reached 6 to 7 log cfu/g. After fermentation, sufu samples were aged in a solution of 10% alcohol + 12% NaCl. After 1 month of aging, the total bacterial count was 6 to 7 log cfu/g, but all foodborne pathogens and mold were reduced to nondetectable levels. The total bacterial count decreased after aging for 2 months and 3 months, but the differences were not significant (P > 0.05) compared with the count after 1 month. Microorganism in experimental sufu from different aging periods and in commercial sufu were compared. A total of 270 isolates were purified and identified by the BBL Crystal Identification System. From the experimental sufu samples, 49 Bacillus spp. (20.4%), 167 Enterococcus spp. (69.6%), 6 Shewanella putrefaciens (2.4%), and 18 miscellaneous gram-negative bacilli (7.5%) were identified. From commercial sufu samples, 17 Bacillus spp. (56.7%), 2 Enterococcus durans (6.7%), 5 miscellaneous gram-negative bacilli (16.7%), 5 Corynbacterium aquaticum (16.7%), and 1 Shewanella putrefaciens (3.3%) were obtained. Although the longer aging period did not significantly decrease the total bacterial count, it may help in the development of sufu flavor. This study showed that sufu fermentation and aging can control common foodborne pathogens, so sufu is a safe product even though its preparation does not include pasteurization.     

Lycopene in tomatoes: chemical and physical properties affected by food processing

Lycopene is the pigment principally responsible for the characteristic deep-red color of ripe tomato fruits and tomato products. It has attracted attention due to its biological and physicochemical properties, especially related to its effects as a natural antioxidant. Although it has no provitamin A activity, lycopene does exhibit a physical quenching rate constant with singlet oxygen almost twice as high as that of beta-carotene. This makes its presence in the diet of considerable interest. Increasing clinical evidence supports the role of lycopene as a micronutrient with important health benefits, because it appears to provide protection against a broad range of epithelial cancers. Tomatoes and related tomato products are the major source of lycopene compounds, and are also considered an important source of carotenoids in the human diet. Undesirable degradation of lycopene not only affects the sensory quality of the final products, but also the health benefit of tomato-based foods for the human body. Lycopene in fresh tomato fruits occurs essentially in the all-trans configuration. The main causes of tomato lycopene degradation during processing are isomerization and oxidation. Isomerization converts all-trans isomers to cis-isomers due to additional energy input and results in an unstable, energy-rich station. Determination of the degree of lycopene isomerization during processing would provide a measure of the potential health benefits of tomato-based foods. Thermal processing (bleaching, retorting, and freezing processes) generally cause some loss of lycopene in tomato-based foods. Heat induces isomerization of the all-trans to cis forms. The cis-isomers increase with temperature and processing time. In general, dehydrated and powdered tomatoes have poor lycopene stability unless carefully processed and promptly placed in a hermetically sealed and inert atmosphere for storage. A significant increase in the cis-isomers with a simultaneous decrease in the all-trans isomers can be observed in the dehydrated tomato samples using the different dehydration methods. Frozen foods and heat-sterilized foods exhibit excellent lycopene stability throughout their normal temperature storage shelf life. Lycopene bioavailability (absorption) can be influenced by many factors. The bioavailability of cis-isomers in food is higher than that of all-trans isomers. Lycopene bioavailability in processed tomato products is higher than in unprocessed fresh tomatoes. The composition and structure of the food also have an impact on the bioavailability of lycopene and may affect the release of lycopene from the tomato tissue matrix. Food processing may improve lycopene bioavailability by breaking down cell walls, which weakens the bonding forces between lycopene and tissue matrix, thus making lycopene more accessible and enhancing the cis-isomerization. More information on lycopene bioavailability, however, is needed. The pharmacokinetic properties of lycopene remain particularly poorly understood. Further research on the bioavalability, pharmacology, biochemistry, and physiology must be done to reveal the mechanism of lycopene in human diet, and the in vivo metabolism of lycopene. Consumer demand for healthy food products provides an opportunity to develop lycopene-rich food as new functional foods, as well as food-grade and pharmaceutical-grade lycopene as new nutraceutical products. An industrial scale, environmentally friendly lycopene extraction and purification procedure with minimal loss of bioactivities is highly desirable for the foods, feed, cosmetic, and pharmaceutical industries. High-quality lycopene products that meet food safety regulations will offer potential benefits to the food industry.     

BMP signaling is required for heart formation in vertebrates

In these studies, we have taken advantage of a transient transgenic strategy in Xenopus embryos to demonstrate that BMP signaling is required in vivo for heart formation in vertebrates. Ectopic expression of dominant negative Type I (tALK3) or Type II (tBMPRII) BMP receptors in developing Xenopus embryos results in reduction or absence of heart formation. Additionally, blocking BMP signaling in this manner downregulates expression of XNkx2-5, a homeobox gene required for cardiac specification, prior to differentiation. Notably, however, initial expression of XNkx2-5 is not affected. Mutant phenotypes can be rescued by co-injection of mutant with wild-type receptors or co-injection of mutant receptors with XSmad1, a downstream mediator of BMP signaling. Whole-mount in situ analyses indicate that ALK3 and XSmad1 are coexpressed in cardiogenic regions. Together, our results demonstrate that BMP signaling is required for maintenance of XNkx2-5 expression and heart formation and suggest that ALK3, BMPRII, and XSmad1 may mediate this signaling.     

Recombinant expression of alpha-bungarotoxin in Pichia pastoris facilitates identification of mutant toxins engineered to recognize neuronal nicotinic acetylcholine receptors

A snake venom-derived alpha-neurotoxin, alpha-bungarotoxin (alphaBgtx), is the classic competitive antagonist of nicotinic acetylcholine receptors (nAChRs). The very high specificity and essentially irreversible binding of alphaBgtx to various nAChRs make alphaBgtx the prime candidate for studying the molecular determinants of specificity for nAChR-ligand interactions. To facilitate site-directed mutagenesis of alphaBgtx for functional analysis, we have developed a recombinant expression system for alphaBgtx using the methylotropic yeast Pichia pastoris. A synthetic gene coding for alphaBgtx was subcloned into an expression vector that directs secretion of the recombinant alphaBgtx (rBgtx) when stably integrated into the yeast genome. Expression of rBgtx was induced by growth of yeast cultures with methanol as the sole carbon source. The activity of the rBgtx in the cell-free medium was measured by competition with 1251-Bgtx for binding to Torpedo nAChR-enriched membranes. The rBgtx, purified to homogeneity by standard HPLC, has the correct predicted amino terminal sequence and molecular mass. Its circular dichroism spectrum is very similar to that of authentic venom-derived alphaBgtx, and the biological activity of the rBgtx is identical to that of authentic alphaBgtx. We have used the Pichia expression system to study a double point mutation of alphaBgtx, rBgtx-K38P/L42Q, that has a high affinity for alpha3beta2 neuronal nAChRs. This is the first demonstration of engineering an alpha-neurotoxin to recognize non-alpha7 neuronal nicotinic receptors.