Polarized epithelium-sperm co-culture system reveals stimulatory factors for the secretion of mouse epididymal quiescin sulfhydryl oxidase 1

Spermatozoa acquire fertilization ability through post-translational modifications. These membrane surface alterations occur in various segments of the epididymis. Quiescin sulfhydryl oxidases, which catalyze thiol-oxidation reactions, are involved in disulfide bond formation, which is essential for sperm maturation, upon transition and migration in the epididymis. Using castration and azoospermia transgenic mouse models, in the present study, we showed that quiescin sulfhydryl oxidase 1 (QSOX1) protein expression and secretion are positively correlated with the presence of testosterone and sperm cells. A two-dimensional in vitro epithelium-sperm co-culture system provided further evidence in support of the notion that both testosterone and its dominant metabolite, 5α-dihydrotestosterone, promote epididymal QSOX1 secretion. We also demonstrated that immature caput spermatozoa, but not mature cauda sperm cells, exhibited great potential to stimulate QSOX1 secretion in vitro, suggesting that sperm maturation is a key regulatory factor for mouse epididymal QSOX1 secretion. Proteomic analysis identified 582 secretory proteins from the co-culture supernatant, of which 258 were sperm-specific and 154 were of epididymal epithelium-origin. Gene Ontology analysis indicated that these secreted proteins exhibit functions known to facilitate sperm membrane organization, cellular activity, and sperm-egg recognition. Taken together, our data demonstrated that testosterone and sperm maturation status are key regulators of mouse epididymal QSOX1 protein expression and secretion.     

浅析我国奶酪行业的发展现状和标准体系

研发一种新型富含新鲜牛油果的奶油奶酪产品。

在奶油奶酪的生产过程中添加不同含量牛油果(0%、10%、20%和30%),并在储存期间(28 d)使用色度计、流变仪、质地分析仪和共聚焦激光扫描显微镜以及感官评价等方法,分析奶油奶酪的化学成分、析水率、黏度、色泽、微观结构和质地等指标的动态变化。

与普通奶油奶酪相比,添加牛油果的样品质地更柔软、延展性更低,但其他理化性质以及微观结构无显著变化。感官测试表明：70.9%的消费者更愿意选择添加了牛油果的奶油奶酪。在长期储存过程中,添加牛油果会导致奶油奶酪的色泽发生变化,有害微生物数量增加。

奶油奶酪中添加牛油果不会显著改变产品的理化性质,添加20%牛油果的新型奶油奶酪产品更受消费者欢迎。

     

Global scale forest function and distribution

A model is described for predicting the dynamic changes in theproportion of tree, shrub and grass life forms at the globalscale. This model is driven by the impacts of climate, soilsand CO₂ on global vegetation leaf area index and net primaryproductivity. The life-form model has been used to explore theinfluences of global warming and continued CO₂ increase on treecover This reflects a realization from other modelling workthat forested vegetation, at the global scale, exerts significantinfluences on climate, and so it is important to assess thepotential for this feedback under climatic change. An increase in CO₂ from 350 to 560 p.p.m. is modelled to haveonly a small impact on tree cover, under current climate. Aregionally-consistent and global increase in temperature ofc.2^{ring}C and a 10 per cent increase in precipitation, butwith no increase in CO₂, indicates a significant potential fortrees to spread into current shrub tundra, over a period of50 years This could lead to regional warming, through changesin winter albedo. The effect of the CO₂ increase is most noticeablein interaction with increases in temperature (2^{ring}C) andprecipitation (10 per cent). In this case the life-form modelprojects further increases in tree cover, particularly in areaswith seasonally low periods of precipitation.     

The Study and Prospect of the Secondary Clarifier Models in Wastewater Treatment

The paper reviews the research status of the secondary clarifier model from one-dimensional model to three-dimensional model. The one-dimensional model based on solid flux theory was outlined by discussing how to choose model parameters such as settling velocity function and the number of layers. Based on the achievement of actived sludge model and the development of wastewater treatment technology, it is suggested that the development of the secondary clarifier model should focus on the establishment of some clarifier model including biological processes and the enrichment of hydraulics phenomena modeling.     

The genesis and classification of soils on wet terraces and moraines in New Zealand

Six soils on glacial outwash terraces and one on moraine are discussed; four are formed partly in loess of unknown age. Evidence of podzolization is apparent in all profiles, but the vertical drainage under very high rainfall is insufficient to remove surplus water. Gley processes appear to dominate, in a perched-water environment.
Podzolic B horizons were identified in the same five profiles following both the Canadian system and that used by the Soil Survey of England and Wales. However, only three of these profiles could be allocated to existing podzolic subgroups in the latter system. Spodic horizons were identified in a different group of five profiles. Differences in classification are discussed with reference to the criteria used and in relation to proposals for revision of the New Zealand Soil Classification.     

Physicochemical methods for pharmacokinetic and residue analysis of chloramphenicol and degradation products in dairy cows

The disposition of chloramphenicol after intramammary and intravenous administration was followed through determinations of chloramphenicol in blood and milk by means of high-performance differential pulse polarography. The concentration-time curves obtained reflected the different modes of administration, and allowed calculation of some pharmacokinetic parameters. The results of the polarographic determination in blood agreed fairly well with those of the microbiological assay in serum. Several body fluids and tissues of the cows were examined for residues of chloramphenicol and degradation products, both by the microbiological method and by high-performance liquid chromatography with ultraviolet detection. In urine, chloramphenicol and chloramphenicol glucuronide were found; in the other fluids and tissues only now and then a trace of chloramphenicol or a degradation product was detected. From these results it appears that chloramphenicol and degradation products are eliminated rapidly and completely after intravenous or intrammary application. No accumulation of degradation products occurred.