海洋菌W11产中温淀粉酶的酶学特性

本研究从威海文登海域筛选获得一株产淀粉酶海洋菌W11,初步鉴定为弧菌,并探讨pH、温度、无机离子对淀粉酶活性和稳定性的影响及该酶底物浓度效应和Km值。结果表明:在pH7.5左右酶活性最高,pH在4.0～7.5范围内体现较强的稳定性。最适酶解温度为55℃,酶液在60℃以下有较好的热稳定性;Ba2+、Mn2+对淀粉酶有激活作用,而Cu2+、Mg2+、Zn2+则抑制淀粉酶活性,表观Km值为0.973mg/mL。海洋菌W11所产的中温淀粉酶保存温度范围较广、适应pH作用的范围广及稳定性较强,将有着广泛的应用潜力。     

Modeling Harvest Intensity of Sooty Shearwater Chicks by Rakiura Māori in New Zealand

Abstract: Cultural evidence suggests that sooty shearwater (Puffinus griseus) chicks have been harvested by Rakiura Māori on islands in southern New Zealand since prehistoric times. Concerns exist that modern harvests may be impacting sooty shearwater abundance. We modeled human-related and ecological determinants of harvest (total no. of individuals harvested) of sooty shearwater chicks on 11 islands and examined the relationship between shearwater abundance and harvesting rates (chicks/hr) and harvester behavior throughout the harvesting season. Models best explaining variation in harvest between harvesting areas (manu), for both the early and late parts of the harvesting season, included harvester-days (included in all models with change in deviance information criteria [ΔDIC], ΔDIC < 8.36 and ΔDIC < 11.5, for the early and late periods, respectively). Other harvest determinants included shearwater density, size of the manu, and number of people helping harvesters (all included in the top 5 models within ΔDIC = 2.25 for the late period). Areas harvested by several families under a common-property harvesting system had higher harvest intensity for their size (24% points higher, 95% credible interval 11–36%) than those managed as an exclusive resource for one family. The slowest harvesters spent more time harvesting but on average only harvested 36% (95% credible interval 15–65%) and 34% (95% credible interval 12–63%) of the harvest taken by the fastest harvesters during the early and late periods, respectively. Our results highlight the possibility of elevated harvest intensity as the population of harvesters increases. However, our models suggested that a corresponding reduction in harvesting rate at low prey densities during the most productive period could potentially regulate harvest intensity. Future research will integrate these results into prospective shearwater demographic models to assess the utility of a range of harvesting strategies in ensuring harvest sustainability.     

毛竹林土壤酶活性变化的海拔效应

在毛竹分布南缘的中亚热带与南亚热带气候过渡区,选择土壤类型、坡度、坡向、经营水平等一致的3个海拔高度(低海拔90～120m、中海拔360～400m、高海拔700～780m)毛竹林,对其土壤酶活性和物理、化学性质进行了测定。磷酸酶、蔗糖酶和脲酶活性分别为0.031～0.042、0.104～0.146和0.017～0.039mg·g-1.h-1,中海拔是3种酶活性显著变化的转折点。蛋白酶活性为0.248～0.259mg·g-1.h-1,随海拔的升高酶活性缓慢提高。过氧化氢酶活性为0.097～0.143mg·g-1.h-1,随海拔的升高酶活性显著上升。不同海拔高度毛竹林土壤物理性质对土壤酶活性无显著影响。土壤有机质、全氮、碱解氮含量与土壤酶活性呈显著或极显著正相关,pH值对土壤酶活性具正效应,海拔梯度上的土壤全磷、全钾、速磷、速钾含量对土壤酶活性影响不显著。不同种类土壤酶活性间呈显著或极显著相关,酶促反应具专一性和共同性特点。     

Can you shrinkwrap a cow? Protections available for the intellectual property of the animal breeding industry

There are currently four main intellectual property protection statutory schemes available: copyright, trade secret, trademark and patent. Each of these protects a different aspect of intellectual property, which leaves gaps of protection when an innovation does not fit squarely within the boundaries of the statutes. Contracts allow the industry to tailor the protection desired. One very common approach is to license the product via contract. Licences allow intellectual property owners to retain ownership and give permission to others to use the product. Although there are several types of licences, the most common is the field of use licence, which limits the licensee's use of the product. This often leads to price discrimination where various levels of restriction are offered at corresponding prices. The more rights retained by the owner, the more restricted the buyer is and the lower the purchase price allowing customers to choose the level of restriction they are willing to accept. Therefore, the different uses and needs of various customers can be accounted for and reflected in the price. The animal breeding industry is currently struggling to protect their innovations falling into these statutory gaps. The protection for animal breeding industry innovations is most likely through contract law rather than traditional intellectual property law. By taking advantage of the unique nature of contracts, industry will be able to tailor protection and pricing to best suit the variety of customers and uses for the products sold.     

Electrophysical characteristics of Azospirillum brasilense Sp245 during interaction with antibodies to various cell surface epitopes

This work was undertaken to examine the electrooptical characteristics of cells of Azospirillum brasilense Sp245 during their interaction with antibodies developed to various cell surface epitopes. We used the dependences of the cell suspension optical density changes induced by electroorientation on the orienting field frequency (740, 1000, 1450, 2000, and 2800kHz). Cell interactions with homologous strain-specific antibodies to the A. brasilense Sp245 O antigen and with homologous antibodies to whole bacterial cells brought about considerable changes in the electrooptical properties of the bacterial suspension. When genus-specific antibodies to the flagellin of the Azospirillum sheathed flagellum and antibodies to the serologically distinct O antigen of A. brasilense Sp7 were included in the A. brasilense Sp245 suspension, the changes caused in the electrooptical signal were slight and had values close to those for the above changes. These findings agree well with the immunochemical characteristics of the Azospirillum O antigens and with the data on the topographical distribution of the Azospirillum major cell surface antigens. The obtained results can serve as a basis for the development of a rapid test for the intraspecies detection of microorganisms.     

Preparation, crystal structure and magnetic property of a binuclear oxalate-bridged iron(III) compound: Fe2(C2O4)Cl4(DMF)4 (DMF = dimethylformamide)

An oxalato-bridged binuclear iron(III) compound, Fe₂(C₂O₄)Cl₄(DMF)₄ (DMF = dimethylformamide), was obtained by electrocrystallization for three weeks at 3.4 V and it displays a strong antiferromagnetic interaction of J = −6.74(4) cm⁻¹.     

硫对石灰性土壤化学性质的影响

通过连续两茬油菜盆栽试验,分析了硫对土壤pH、电导率、交换性阳离子和水溶性阴离子等指标的影响.结果表明：硫能显著降低土壤pH、增加土壤电导率;施硫会使土壤交换性Na⁺和交换性K⁺含量升高,并加剧土壤水溶性阴离子总量的累积;施硫对交换性Ca²⁺和Mg²⁺含量影响较小,也未能显著改变土壤阳离子交换量和土壤碱化度.与尿素相比,硫包膜尿素对土壤pH和电导率的影响不显著,但对交换性阳离子和水溶性阴离子影响较大;与尿素处理相比,施硫未表现出明显的增产效应;施硫较多时,油菜产量显著降低.     

Diversity of salt-tolerant culturable aerobic microorganisms on historic buildings in Southern Brazil

Halotolerant and halophilic microorganisms may be expected to be present on the external walls of buildings, especially in dry and/or hot climates. They have been detected in Europe in various molecular biological studies. Using plating on specific salt-supplemented medium (10 and 15%), bacteria and fungi were detected in winter, spring and summer months on the discoloured external walls of 5 historic buildings in Porto Alegre, South Brazil. Microbial biodiversity in the samples was calculated using the Simpson Index. Halotolerant non-phototroph diversity was highest in the winter (September), when environmental conditions are less extreme. Some collections yielded organisms that grew on media with 15% added salt; diversity in this case was lower. Frequently, and in all winter collections, only one type of microorganism grew; this was a brown-pigmented fungus, probable genus Cladosporium. Greater diversity was found at 15% salt in 2 collections made in the summer month of January. It is suggested that this results from the selection of organisms able to resist the more extreme conditions of high temperature and lower relative humidity.     

Landward changes of soil enzyme activities in a tidal flat wetland of the Yangtze River Estuary and correlations with physico-chemical factors

The landward changes of soil enzyme activities and physico-chemical properties of the surface sediment in Chongming Dongtan of the Yangtze River Estuary, were studied. Along the elevation gradient or succession series, the contents of total phosphorus (TP), total nitrogen (TN) and organic matter (OM) in the sediment increased, but the average grain size (AGS) of the sediment and the content of the dissolved inorganic phosphorus (DIP) decreased. The activity of alkaline phosphatase increased gradually along the elevation gradient, and was positively correlated with the values of TP, TN and OM (P<0.05), but negatively to AGS and DIP (P<0.05). It was correlated with a mechanism of substrate inductivity and product inhibition. Catalase activity had the similar trend of gradual increase along the elevation gradient, enhancing the fertility of the soil and the oxidative process of OM in the sediment. Along the succession series, from the tidal flat to the bulrush (Scirpus mariqueter) zone, and then to the reed (Phragmites australis) zone, the activity of sucrase only changed insignificantly, but there was a higher activity in the bulrush zone than in other zones. The activity of proteinase decreased from the tidal flat to the reed zone, and the activity was negatively correlated with OM and TN (P<0.05), but positively with DIP (P<0.05). Through the succession zones a decrease in the number of diatoms resulted in a decline in the concentration of protein, which influenced the proteinase activity, suggesting that the proteinase in the sediment was produced by diatoms.     

Climate and pH as determinants of vegetation succession in Central European man‐made habitats

Questions: (1) What are the most important abiotic environmental variables influencing succession in central European man‐made habitats? (2) How do these variables interact with one another and with variation in community properties? Location: Central, western and southern parts of the Czech Republic. Habitats included old fields, urban sites, spoil heaps after coal mining, sites at water reservoirs, extracted sand pit and peatland and reclaimed sites in areas deforested by air pollution. Methods: We investigated vegetation patterns on 15 succes‐sional seres, sampled by the same methods. Time of succession over which the data were available ranged from 12 to 76 years. The cover of vascular plant species (in %) was estimated in 5 m × 5 m plots. The relationships between vegetation characteristics (species composition, total cover, cover of woody species, species number and rate of dominant species turnover) and 13 abiotic site factors, including climatic and soil variables, were tested using CCA ordination and regression models. Results: Substratum pH, the only substratum characteristic, and climate were the environmental variables significantly affecting the vegetation patterns in the course of succession. The rate of succession, measured as the turnover of dominant species, was significantly more rapid in lowland than in mountain climates. On alkaline soils, species numbers in succession increased towards warmer climates. However, acid soils prevented any increase in species numbers, regardless of the climate. Surprisingly, forms of nitrogen and contents of C, P and cations did not exhibit any significant effect on the vegetation characteristics studied. Conclusions: Our approach, to compare a number of seres, can contribute not only to our understanding of succession, but also to help restoration projects to predict vegetation change because the crucial environmental variables, as identified by this study, are easy to measure.